リソースの使用
１、［Myproject］→［リソース］でリソースを追加する
２、コードで制御する
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
PictureBox1.Image = My.Resources.Image1
PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
End Sub
名前空間の参照
［MyProject］→［参照］で参照設定
※参照することでSystem.IOを省略できる！
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If Directory.Exists(TextBox1.Text) Then
Label1.Text = "発見！"
Else
Label1.Text = "ないです"
End If
End Sub
変数の定義
Dim a As String
a = "hello"
Dim x As Integer = 1000
Dim weight As Single, height As Single
リテラル値のデータ型
Dim x1 = 100I 'integer型
Dim x2 = 100.0F 'single型
Null許容型
Dim x1 As Nullable(Of Integer)
Dim x2 As Integer?
定数
Const APPLI As String = "Visual Basic"
Const TIPS_NUM As Integer = 1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Const STR As String = "の学習"
Label1.Text = APPLI & STR & TIPS_NUM
End Sub
列挙型
Public Class Form1
Private Enum ClassType
special '0
standard '1
basic '2
End Enum
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim test As ClassType
Select Case ComboBox1.SelectedItem
Case CInt(ClassType.special)
test = ClassType.special
Case CInt(ClassType.standard)
test = ClassType.standard
Case CInt(ClassType.basic)
test = ClassType.basic
End Select
Label1.Text = test.ToString()
End Sub
End Class
※列挙型はメソッド内で宣言できない。
※１つのメンバーの値を指定したとき、次のメンバーにはその値に１を加えた値が自動的に設定される。
データ型を変換
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim i As Integer = 30
Dim lng As Long = i '暗黙の型変換
Dim d As Double = 123.456
i = CInt(d) 'キャスト（桁落ち）
Label1.Text = i
Dim o As Object = i '暗黙の型変換
o = "VISUAL BASIC 2017"
Dim s1 As String = DirectCast(o, String)
Dim s2 As String = TryCast(o, String)
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim d As Double
d = Double.Parse(TextBox1.Text)
Me.Label1.Text = d.ToString()
End Sub
メッセージボックス
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ret = MessageBox.Show("ボタンをクリックしてください", "通知",
MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question)
Select Case ret
Case DialogResult.Yes
Label1.Text = "[はい]がクリックされました"
Case DialogResult.No
Label1.Text = "[いいえ]がクリックされました"
Case DialogResult.Cancel
Label1.Text = "[キャンセル]がクリックされました"
End Select
End Sub
改行やタブの挿入
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim s1 As String = "ワイン"
Dim s2 As String = "チーズ"
Label1.Text = "C:\VB2017\Sample.txt"
Label2.Text = """C:\VB2017\Sample.txt"""
Label3.Text = s1 & ControlChars.Lf & s2
Label4.Text = $"{s1}{ControlChars.Lf}{s2}"
End Sub
Object型
Public Class Form1
Private Function sampleMethod(x As Object) As Object
If TypeOf x Is String Then
Return 365
Else
Return "文字列を返す"
End If
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim o As Object
o = sampleMethod("SAMPLE")
Label1.Text = o.ToString()
o = sampleMethod(15)
Label2.Text = o.ToString()
End Sub
End Class
プログラムの終了
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ret = MessageBox.Show("アプリケーションを終了しますか？", "確認",
MessageBoxButtons.YesNo)
If ret = DialogResult.Yes Then
Application.Exit()
End If
End Sub
加減乗除
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim X As Integer = 100
Label1.Text = (X / 20).ToString()
X += 20
Label2.Text = X.ToString()
End Sub
複数条件の判断
Public Class Form1
Private Function Check1()
Label2.Text += " Check1呼び出し"
Return CheckBox1.Checked
End Function
Private Function Check2()
Label2.Text += " Check2呼び出し"
Return CheckBox2.Checked
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Label2.Text = ""
Dim ret = Check1() And Check2()
Label1.Text = "And演算子の結果：" + ret.ToString()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Label2.Text = ""
Dim ret = Check1() AndAlso Check2()
Label1.Text = "AndAlso演算子の結果：" + ret.ToString()
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Label2.Text = ""
Dim ret = Check1() Or Check2()
Label1.Text = "Or演算子の結果：" + ret.ToString()
End Sub
Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
Label2.Text = ""
Dim ret = Check1() OrElse Check2()
Label1.Text = "OrElse演算子の結果：" + ret.ToString()
End Sub
End Class
型のキャストが可能か調べる
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
For Each o As Control In Controls
If TypeOf o Is CheckBox Then
o.Text = "clicked!"
End If
Next
End Sub
絶対値
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim x As Integer = -1234
MessageBox.Show(x & "の絶対値：" & Math.Abs(x).ToString, "確認")
End Sub
平方根
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim x As Double = 3.0
MessageBox.Show(x & "の平方根" & Math.Sqrt(x).ToString, "確認")
End Sub
乱数
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim rnd = New Random()
Label1.Text = rnd.Next(100)
Label2.Text = rnd.Next(100, 1001)
End Sub
現在の日付と時刻取得
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt = DateTime.Now
'xxxx年xx月xx日 xxxx/xx/xx
Label1.Text = dt.ToLongDateString() & vbNewLine & dt.ToShortDateString
'xx:xx:xx xx:xx
Label2.Text = dt.ToLongTimeString() & vbNewLine & dt.ToShortTimeString
Label3.Text = dt.ToString()
End Sub
日付要素取得
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt = DateTime.Now
Label1.Text = dt.Year
Label2.Text = dt.Month
Label3.Text = dt.Day
End Sub
曜日取得
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt = DateTime.Today
Select Case dt.DayOfWeek
Case DayOfWeek.Sunday
Label1.Text = "日曜日"
Case DayOfWeek.Monday
Label1.Text = "月曜日"
Case DayOfWeek.Tuesday
Label1.Text = "火曜日"
Case DayOfWeek.Wednesday
Label1.Text = "水曜日"
Case DayOfWeek.Thursday
Label1.Text = "木曜日"
Case DayOfWeek.Friday
Label1.Text = "金曜日"
Case DayOfWeek.Saturday
Label1.Text = "土曜日"
End Select
End Sub
一定期間前や後の日付、時刻を求める
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt = DateTime.Now
Label1.Text = dt
Label2.Text = dt.AddHours(-5)
Label3.Text = dt.AddDays(10)
End Sub
2つの日時の間隔を求める
Public Class Form1
Private sTime As DateTime
Private eTime As DateTime
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
sTime = DateTime.Now
Label1.Text = ""
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
eTime = DateTime.Now
Dim ts = eTime.Subtract(sTime) 'TimeSpan型
If ts.Seconds = 10 Then
Label1.Text = "おめでとう " & ts.TotalSeconds.ToString("##.##")
Else
Label1.Text = "残念" & ts.TotalSeconds.ToString("##.##")
End If
End Sub
End Class
任意の時間間隔を作成
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ts1 = New TimeSpan(20, 10, 5) '20時間10分5秒
Dim ts2 = New TimeSpan(0, 25, 20, 15) '0日25時間20分15秒
Dim ts3 = New TimeSpan(0, 0, 0, 0, 1001) '0秒1001ミリ秒
Label1.Text = ts1.ToString()
Label2.Text = ts2.ToString()
Label3.Text = ts3.ToString()
End Sub
任意の日付を作成
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt1 = New DateTime(2018, 2, 25)
Dim dt2 = New DateTime(2018, 5, 1, 12, 34, 56)
Label1.Text = dt1.ToString()
Label2.Text = dt2.ToString()
End Sub
現在の月の日数を取得
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Label1.Text = DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month)
End Sub
日付文字列を日付データにする
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt As DateTime
Dim ret = DateTime.TryParse(TextBox1.Text, dt)
If ret Then
Label1.Text = dt
Else
Label1.Text = "変換不可"
End If
End Sub
ifステートメント
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt As DateTime
If TextBox1.Text = "" Then
Label1.Text = "入力されていません"
ElseIf DateTime.TryParse(TextBox1.Text, dt) Then
Label1.Text = "入力した日付：" & dt
Else
Label1.Text = "正しい日付を入力してください"
End If
End Sub
selectステートメント
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Select Case ComboBox1.Text
Case "オレンジ"
BackColor = Color.Orange
Case "ブルー"
BackColor = Color.Blue
Case "イエロー"
BackColor = Color.Yellow
Case Else
BackColor = Color.Empty
End Select
End Sub
forステートメント
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
ListBox1.Items.Clear()
For i = 1 To 10
ListBox1.Items.Add("No." & i)
Next
End Sub
whileステートメント
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim i As Integer = 1
ListBox1.Items.Clear()
While i < 11
ListBox1.Items.Add("No." & i)
i += 1
End While
End Sub
doステートメント
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim i = 11
ListBox1.Items.Clear()
Do
ListBox1.Items.Add("No." & i)
i += 1
Loop While i <= 10
End Sub
配列の処理の繰り返し
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim str = ""
For Each chk As CheckBox In GroupBox1.controls
If chk.Checked = True Then
str += chk.Text & ControlChars.Tab
End If
Next
If str <> "" Then
MessageBox.Show(str & ControlChars.Lf & "が選ばれました", "確認")
End If
End Sub
ループの途中で処理を先頭に戻す
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim str1 = ""
Dim str2 = ""
For Each chk As RadioButton In GroupBox1.Controls
If chk.Checked = True Then
str1 += chk.Text & " "
Continue For
Else
str2 += chk.Text & ""
End If
Next
If str1 <> "" Then
MessageBox.Show(str1 & vbLf & "が選択されました" & vbLf &
str2 & vbLf & "が選択されませんでした", "確認")
End If
End Sub
if関数
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt = DateTime.Today
Dim RetStr = If(dt.Day <= 15, "前半", "後半")
Label1.Text = $"今日の日付：{dt}" & ControlChars.Lf &
$"月の{RetStr}です。"
End Sub
配列
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ary = New Integer(4) {}
Label1.Text = ""
For i As Integer = 0 To 4
ary(i) = i * 2
Label1.Text += $"ary[{i}] = {ary(i)}" & ControlChars.Lf
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim ary = New Integer(1, 2) {}
Label1.Text = ""
For i As Integer = 0 To 1
For j As Integer = 0 To 2
ary(i, j) = i + j
Label1.Text += $"ary[{i},{j}] = {ary(i, j)}"
Next
Label1.Text += ControlChars.Lf
Next
End Sub
End Class
配列の宣言時に値入れる
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim names As String() = {"田中", "佐藤", "高橋", "伊藤", "清水"}
Dim i As Integer
If ComboBox1.SelectedIndex = -1 Then
Label1.Text = "クラスを選択してください"
Return
End If
i = ComboBox1.SelectedIndex
Label1.Text = ComboBox1.SelectedItem + $"組の担任：{names(i)}先生"
End Sub
配列の要素数を求める
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim Xary = New Integer(4) {}
Dim yAry = New Integer(1, 2) {}
Label1.Text = $"xAry(4)の要素数：{Xary.Length}"
Label2.Text = $"yAry(1,2)の全要素数：{yAry.Length}" & vbLf &
$"一つ目の要素数：{yAry.GetLength(0)}" & vbLf &
$"二つ目の要素数：{yAry.GetLength(1)}"
End Sub
配列の要素数を変更
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ary = New String() {"東京", "名古屋", "大阪"}
Label1.Text = "配列aryの要素数：" & ary.Length & vbLf
Label1.Text &= $"ary(0)={ary(0)},ary(1)={ary(1)},ary(2)={ary(2)}"
ary = New String(4) {}
Label2.Text = "配列aryの要素数：" & ary.Length & vbLf
Label2.Text &= $"ary(0)={ary(0)},ary(1)={ary(1)},ary(2)={ary(2)}"
End Sub
ジャグ配列
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim student = New Integer(2)() {}
student(0) = New Integer(2) {37, 35, 34}
student(1) = New Integer(1) {41, 43}
student(2) = New Integer(3) {33, 34, 33, 35}
ListBox1.Items.Clear()
For i = 0 To student.Length - 1
ListBox1.Items.Add($"{i + 1}年")
For j = 0 To student(i).Length - 1
ListBox1.Items.Add($" {j + 1}組：{student(i)(j)}")
Next
Next
End Sub
配列の要素並べ替え
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim apli = New String() {"PowerPoint", "Excel", "Word", "Access"}
ListBox1.Items.Clear()
ListBox2.Items.Clear()
ListBox3.Items.Clear()
ListBox1.Items.AddRange(apli)
Array.Sort(apli)
ListBox2.Items.AddRange(apli)
Array.Reverse(apli)
ListBox3.Items.AddRange(apli)
End Sub
配列をクリア
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ary = New String() {"東京", "名古屋", "大阪"}
Label1.Text = $"ary(0)={ary(0)},ary(1)={ary(1)},ary(2)={ary(2)}"
Array.Clear(ary, 1, 2)
Label2.Text = $"ary(0)={ary(0)},ary(1)={ary(1)},ary(2)={ary(2)}"
End Sub
配列をコピー
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ary1 = {10, 20, 30}
Dim ary2 = {6, 7, 8, 9, 0}
Dim ary3 = ary1.Clone()
Dim ary4 = ary1
ary1.CopyTo(ary2, 2)
ary1(0) = 99
Label1.Text = "ary1 = "
Label2.Text = "ary2 = "
Label3.Text = "ary3 = "
Label4.Text = "ary4 = "
For i = 0 To ary1.Length - 1
Label1.Text += ary1(i) & " "
Next
For i = 0 To ary2.Length - 1
Label2.Text += ary2(i) & " "
Next
For i = 0 To ary3.Length - 1
Label3.Text += ary3(i) & " "
Next
For i = 0 To ary4.Length - 1
Label4.Text += ary4(i) & " "
Next
End Sub
ArrayListクラス(可変長)
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lst = New ArrayList()
lst.AddRange(ListBox1.Items)
Label1.Text = "最初の要素：" & lst(0)
Label2.Text = "要素数：" & lst.Count
End Sub
Listジェネリッククラス（型指定）
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lst = New List(Of String)()
lst.AddRange(New String() {"味噌", "醤油", "お酢"})
Label1.Text = ""
For i As Integer = 0 To lst.Count - 1
Label1.Text += lst(i) + ControlChars.Lf
Next
End Sub
Listジェネリッククラスの要素並べ替え
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lst = New List(Of String)() From {
"いちご",
"メロン",
"スイカ",
"ぶどう"
}
ListBox1.Items.Clear()
ListBox2.Items.Clear()
ListBox3.Items.Clear()
ListBox1.Items.AddRange(lst.ToArray()) 'ToArrayはリストを配列に変換
lst.Sort()
ListBox2.Items.AddRange(lst.ToArray())
lst.Reverse()
ListBox3.Items.AddRange(lst.ToArray())
End Sub
コレクションの要素から値を検索
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lst = New List(Of String)() From {
"東京",
"品川",
"新横浜"
}
For Each val As Object In ListBox1.Items
lst.Add(val)
Next
Dim ret As Integer = lst.IndexOf(TextBox1.Text)
If ret = -1 Then
Label1.Text = "コレクション内に存在しません"
Else
Label1.Text = TextBox1.Text & "のインデックス：" & ret
End If
End Sub
Dictionaryジェネリッククラス
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dic = New Dictionary(Of String, String)
dic("ex") = "Excel"
dic("pp") = "PowerPoint"
dic.Add("wd", "Word")
dic.Add("ac", "Access")
Label1.Text = dic("wd")
ListBox1.Items.Clear()
For Each myKey As String In dic.Keys
ListBox1.Items.Add(myKey)
Next
ListBox2.Items.Clear()
For Each myVal As String In dic.Values
ListBox2.Items.Add(myVal)
Next
ListBox3.Items.Clear()
For Each myPair In dic
ListBox3.Items.Add(myPair.Key & ControlChars.Tab & myPair.Value)
Next
End Sub
SortedListジェネリッククラス（キーでソートした型指定コレクション）
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lst = New SortedList(Of String, String)
lst("vb") = "Visual Basic"
lst("pp") = "Power Point"
lst.Add("wd", "Word")
lst.Add("ac", "Access")
ListBox1.Items.Clear()
Dim i = 0
For Each it In lst
ListBox1.Items.Add($"{i}：{it.Key}：{it.Value}")
i += 1
Next
lst.Add("ex", "Excel")
ListBox2.Items.Clear()
i = 0
For Each it In lst
ListBox2.Items.Add($"{i}：{it.Key}：{it.Value}")
i += 1
Next
End Sub
コレクションから条件にマッチした要素を取り出す
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lst = New List(Of MyItem)()
lst.Add(New MyItem With {.Key = "vb", .Text = "VisualBasic"})
lst.Add(New MyItem With {.Key = "pp", .Text = "PowerPoint"})
lst.Add(New MyItem With {.Key = "wd", .Text = "Word"})
lst.Add(New MyItem With {.Key = "ac", .Text = "Access"})
ListBox1.Items.Clear()
For Each it In lst
ListBox1.Items.Add($"{it.Key}：{it.Text}")
Next
Dim item = lst.FirstOrDefault(Function(x)
Return x.Key = TextBox1.Text
End Function)
If item Is Nothing Then
Label1.Text = "なし"
Else
Label1.Text = item.Text
End If
End Sub
End Class
Public Class MyItem
Public Property Key As String
Public Property Text As String
End Class
subメソッド
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim xStr As String = "Param"
Dim yStr As String = "Param"
xProc(xStr)
yProc(yStr)
Label1.Text = Convert.ToString("値渡しの結果：") & xStr
Label2.Text = Convert.ToString("参照渡しの結果：") & yStr
End Sub
Private Sub xProc(ByVal xParam As String)
xParam = "Change!"
End Sub
Private Sub yProc(ByRef yParam As String)
yParam = "Change!"
End Sub
End Class
functionメソッド
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ret = proc(10, 20)
Label1.Text = "取得した戻り値：" & ret.ToString()
End Sub
Private Function proc(x As Integer, y As Integer) As Integer
Return x * y
End Function
End Class
配列を受け渡すメソッド
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lstX = {"London", "Paris", "NewYork"}
Dim lstY = proc(lstX)
Label2.Text = ""
For Each city As String In lstY
Label2.Text += city & ControlChars.Lf
Next
End Sub
Private Function proc(lst As String()) As String()
Label1.Text = ""
For Each city In lst
Label1.Text += city & ControlChars.Lf
Next
lst(2) = "tokyo"
Return lst
End Function
End Class
引数の数が可変のメソッド
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
proc(True)
proc(False, "数学")
proc(False, "国語", "社会")
End Sub
Private Sub proc(result As Boolean, ParamArray kamoku As String())
Dim gouhi As String = "合格"
If result = False Then
gouhi = "追試-->"
End If
For Each item As String In kamoku
gouhi += " " & item
Next
MessageBox.Show($"期末試験の結果 ： {gouhi}", "確認")
End Sub
End Class
オーバーロード
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
proc("1月")
proc(2)
End Sub
Private Sub proc(nextMonth As String)
MessageBox.Show("次回の放送は " & nextMonth & " です", "通知")
End Sub
Private Sub proc(nextMonth As Integer)
proc(nextMonth & "月")
End Sub
End Class
クラスのコンストラクター作成
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim obj = New SampleClass("新規お客様")
MessageBox.Show("インスタンス生成", "確認")
End Sub
End Class
Public Class SampleClass
Private _name As String
Private _id As String
Public Sub New(Name As String)
_name = Name
_id = DateTime.Now.ToString("yyyyMMddHHmm")
End Sub
End Class
クラスのプロパティ
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim o = New SampleClass("新規お客様")
o.Name = "やまだはなこ"
MessageBox.Show($"Name:{o.Name}", "確認")
End Sub
End Class
Public Class SampleClass
Private _name As String
Public Property Name() As String
Get
Return _name
End Get
Set(value As String)
_name = value
End Set
End Property
Public Sub New(Name As String)
_name = Name
End Sub
End Class
自動実装プロパティ
Public Class SampleClass
Public Property Name As String
Public Sub New(Name As String)
_name = Name
End Sub
End Class
クラスのメソッド定義
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim o = New SampleClass("新規お客様")
o.ShowData()
MessageBox.Show("氏名：" & o.GetName("山田花子様"), "確認")
End Sub
End Class
Public Class SampleClass
Private _name As String
Public Sub ShowData()
MessageBox.Show("お客様名：" & _name, "確認")
End Sub
Public Function GetName(name As String) As String
If name.EndsWith("様") Then
Return name.Substring(0, name.Length - 1)
Else
Return name
End If
End Function
Public Sub New(Name As String)
_name = Name
End Sub
End Class
クラスのイベント定義
Public Class SampleClass
Public Event MyEvent As Action(Of Object, EventArgs)
Public Event ev As EventHandler
Public Sub MyMethod()
Dim msg As String = DateTime.Now.ToString("HH:mm:ss")
RaiseEvent MyEvent(Me, EventArgs.Empty)
End Sub
End Class
イベントハンドラー作成
Public Class Form1
Private o As New SampleClass
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
AddHandler o.MyEvent, AddressOf o_MyEvent
End Sub
Private Sub o_MyEvent(s As String)
Label1.Text = s
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
o.proc()
End Sub
End Class
Public Class SampleClass
Public Event MyEvent As Action(Of String)
Public Sub proc()
Dim msg As String = DateTime.Now.ToString("HH:mm:ss")
RaiseEvent MyEvent(msg)
End Sub
End Class
オブジェクト生成時にプロパティ設定
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim o As New SampleClass() With {
.Name = "やまだはなこ"
}
End Sub
End Class
Public Class SampleClass
Public Property Name As String
End Class
クラスの継承
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim tel = New SampleClassTel("山田花子", "123456789")
MessageBox.Show($"名前： {tel.Name}", "派生クラス")
End Sub
End Class
Public Class SampleClass
Public ReadOnly Property Name As String
Public Property Id As String
Public Sub New(name As String)
Me.Name = name
Me.Id = DateTime.Now.ToString("yymmddhhmm")
End Sub
End Class
Public Class SampleClassTel
Inherits SampleClass
Public ReadOnly Property Tel As String
Public Sub New(name As String, tel As String)
MyBase.New(name)
Me.Tel = tel
End Sub
End Class
派生クラスで再定義
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim tel = New SampleClassTel("山田花子", "123456789")
tel.ShowData()
End Sub
End Class
Public Class SampleClass
Public Property Name As String
Public Property Id As String
Public Sub New(name As String)
Me.Name = name
Me.Id = DateTime.Now.ToString("yymmddhhmm")
End Sub
Public Overridable Sub ShowData()
MessageBox.Show($"お客様氏名：{Id}-{Name}", "確認")
End Sub
End Class
Public Class SampleClassTel
Inherits SampleClass
Public ReadOnly Property Tel As String
Public Sub New(name As String, tel As String)
MyBase.New(name)
Me.Tel = tel
End Sub
Public Overrides Sub ShowData()
MyBase.ShowData()
MessageBox.Show($"お客様電話番号：{Tel}", "確認")
End Sub
End Class
型情報を引数にするクラス
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim genericStr = New MyGeneric(Of String)() With {
.Value = "Visual Basic"
}
Dim genericInt = New MyGeneric(Of Integer)() With {
.Value = 2017
}
MessageBox.Show(genericStr.Value & " " & genericInt.Value, "確認")
End Sub
End Class
Public Class MyGeneric(Of T)
Private _val As T
Public Property Value() As T
Get
Return _val
End Get
Set(value As T)
_val = value
End Set
End Property
End Class
構造体の定義
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim mn As MyMenu
mn.menuNo = 1
mn.Menu = "みそラーメン"
mn.price = 750
MessageBox.Show("大盛価格->\" & mn.priceBig, mn.Menu)
End Sub
End Class
Public Structure MyMenu
Public menuNo As Integer
Public Menu As String
Public price As Integer
Public ReadOnly Property priceBig() As Integer
Get
Return price + 100
End Get
End Property
End Structure
構造体配列
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim mc = New MyStruct(2) {}
ListBox1.Items.Clear()
For i As Integer = 0 To 2
mc(i).CourseNo = (i + 1).ToString("00")
mc(i).CourseName = "コース名未定"
mc(i).Num = 20
ListBox1.Items.Add(
$"{mc(i).CourseNo}-{mc(i).CourseName}-{mc(i).Num}名")
Next
End Sub
End Class
Public Structure MyStruct
Public CourseNo As String
Public CourseName As String
Public Num As Integer
End Structure
構造体や配列を構造体のメンバーにする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim bs As BurgerSet
Dim setSize = {"S", "M", "L"}
bs.Burger = "チーズバーガー"
bs.Drink.Name = "コーラ"
bs.Drink.Size = setSize
MessageBox.Show(bs.Burger & vbLf &
bs.Drink.Name & vbLf &
bs.Drink.Size(1), "確認")
End Sub
End Class
Public Structure BurgerSet
Public Drink As Drink
Public Burger As String
End Structure
Public Structure Drink
Public Name As String
Public Size As String()
End Structure
構造体を受け取るメソッド
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim mn As StructMenu
mn.MenuNo = 1
mn.Menu = "味噌ラーメン"
mn.Price = 750
showData(mn)
End Sub
Private Sub showData(nMenu As StructMenu)
MessageBox.Show(nMenu.Menu & ":" & nMenu.Price.ToString("0円"), "確認")
End Sub
End Class
Public Structure StructMenu
Public MenuNo As Integer
Public Menu As String
Public Price As Integer
End Structure
構造体を返すメソッド
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim pt As Point
pt = twicePoint(100, 200)
MessageBox.Show(pt.x & " " & pt.y, "戻り値")
End Sub
Public Function twicePoint(x As Integer, y As Integer) As Point
Dim pt As Point
pt.x = x * 2
pt.y = y * 2
Return pt
End Function
End Class
Public Structure Point
Public x As Integer
Public y As Integer
End Structure
タスクの作成
Public Class Form1
Private _task As Task
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
_task = New Task(
Sub()
For i As Integer = 0 To 59
Me.Invoke(New Action(
Sub()
Label1.Text =
DateTime.Now.ToString("HH:MM:ss")
End Sub))
System.Threading.Thread.Sleep(1000)
Next
End Sub)
_task.Start()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
_task = New Task(AddressOf OnWork)
_task.Start()
End Sub
Private Sub OnWork()
For i As Integer = 0 To 59
Me.Invoke(New Action(Sub()
Label1.Text =
DateTime.Now.ToString("HH:MM:mm")
End Sub))
System.Threading.Thread.Sleep(1000)
Next
End Sub
End Class
タスクを作成して実行
Public Class Form1
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Await Task.Factory.StartNew(
Sub()
For i As Integer = 0 To 59
Me.Invoke(New Action(Sub()
Label1.Text =
DateTime.Now.ToString("HH:MM:ss")
End Sub))
System.Threading.Thread.Sleep(1000)
Next
End Sub)
End Sub
Private Async Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim task1 As New Task(
Sub()
For i As Integer = 0 To 59
Me.Invoke(New Action(Sub()
Label1.Text =
DateTime.Now.ToString("HH:MM:ss")
End Sub))
System.Threading.Thread.Sleep(1000)
Next
End Sub)
Await Task.Delay(5000)
task1.Start()
End Sub
End Class
戻り値を持つタスク
Public Class Form1
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ret = Await Task.Factory.StartNew(
Function()
Dim i = 0
While i < 10
Me.Invoke(New Action(
Sub()
Label1.Text =
$"{i}秒経過"
End Sub))
System.Threading.Thread.Sleep(1000)
i = i + 1
End While
Return DateTime.Now
End Function)
Label1.Text = & "最終時刻：{ret}"
End Sub
End Class
タスクの完了を待つ
Public Class Form1
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Await Task.Run(Sub() onTask1())
Await Task.Run(Sub() onTask2())
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Task.Run(Sub() onTask1())
Task.Run(Sub() onTask2())
End Sub
Private Sub onTask1()
Dim i = 0
While i < 10
Me.Invoke(New Action(
Sub()
Label1.Text = $"{i}秒経過"
End Sub))
System.Threading.Thread.Sleep(1000)
i = i + 1
End While
End Sub
Private Sub onTask2()
Dim i = 0
While i < 10
Me.Invoke(New Action(
Sub()
Label2.Text = $"{i}秒経過"
End Sub))
System.Threading.Thread.Sleep(1000)
i = i + 1
End While
End Sub
End Class
複数のタスクの実行を待つ
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Task.Factory.StartNew(
Sub()
Me.Invoke(New Action(
Sub()
Label3.Text = "タスク開始"
End Sub))
Dim task1 = Task.Factory.StartNew(Sub() onTask1())
Dim task2 = Task.Factory.StartNew(Sub() onTask2())
Task.WaitAll(task1, task2)
Me.Invoke(New Action(
Sub()
Label3.Text = "タスク終了"
End Sub))
End Sub)
End Sub
Private Sub onTask1()
Dim i = 0
While i < 5
Me.Invoke(New Action(
Sub()
Label1.Text = $"{i}秒経過"
End Sub))
System.Threading.Thread.Sleep(1000)
i = i + 1
End While
End Sub
Private Sub onTask2()
Dim i = 0
While i < 10
Me.Invoke(New Action(
Sub()
Label2.Text = $"{i}秒経過"
End Sub))
System.Threading.Thread.Sleep(1000)
i = i + 1
End While
End Sub
End Class
非同期メソッドの呼び出し
Public Class Form1
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim sum As Integer = Await onWork()
MessageBox.Show($"合計値 {sum}")
End Sub
Private Function onWork() As Task(Of Integer)
Dim task = New Task(Of Integer)(
Function()
Dim sum As Integer
For i As Integer = 1 To 10
Me.Invoke(New Action(
Sub()
Label1.Text = $"{i}秒経過"
End Sub))
sum += 1
System.Threading.Thread.Sleep(1000)
Next
Return sum
End Function)
task.Start()
Return task
End Function
End Class
タスクの終了時に実行を継続する
Public Class Form1
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Await onWork()
End Sub
Private Function onWork() As Task(Of Integer)
Dim task = New Task(Of Integer)(
Function()
Dim sum As Integer = 0
For i As Integer = 1 To 10
Me.Invoke(New Action(
Sub()
Label1.Text = $"{i}秒追加"
End Sub))
sum += i
System.Threading.Thread.Sleep(1000)
Next
Return sum
End Function)
task.Start()
task.ContinueWith(
Sub(t)
Dim res As Integer = t.Result
Me.Invoke(New Action(
Sub()
Label2.Text = $"合計値：{res}"
End Sub))
End Sub)
Return task
End Function
End Class
スレッドを切り替えてUI変更
Public Class Form1
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
ProgressBar1.Minimum = 0
ProgressBar1.Maximum = 10
Await Task.Factory.StartNew(
Sub()
Dim i As Integer
For i = 1 To 10
Me.Invoke(New Action(
Sub()
Label1.Text = String.Format("{0}秒経過", i)
End Sub))
Me.Invoke(New Action(
Sub()
ProgressBar1.Value = i
End Sub))
System.Threading.Thread.Sleep(1000)
Next
End Sub)
MessageBox.Show("10秒経過しました")
End Sub
End Class
一定時間停止する
Public Class Form1
'Sleepメソッド
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Await Task.Factory.StartNew(
Sub()
Dim i As Integer
For i = 1 To 10
Me.Invoke(New Action(
Sub()
Label1.Text = $"{i}秒経過"
End Sub))
System.Threading.Thread.Sleep(1000)
Next
End Sub)
Label1.Text = "10秒経過"
End Sub
'Delayメソッド
Private Async Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Await Task.Factory.StartNew(
Async Function()
Dim i As Integer
For i = 1 To 10
Me.Invoke(New Action(
Sub()
Label1.Text = $"{i}秒経過"
End Sub))
Await Task.Delay(1000)
Next
End Function)
Label1.Text = "10秒経過"
End Sub
End Class
イベントが発生するまで停止
Public Class Form1
Private mre As System.Threading.ManualResetEvent
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
mre = New System.Threading.ManualResetEvent(False)
Await Task.Factory.StartNew(
Sub()
Dim i As Integer
For i = 1 To 20
If i = 10 Then
Me.Invoke(New Action(
Sub()
Label1.Text = "解除イベント待ち"
End Sub))
mre.Reset()
mre.WaitOne()
End If
Me.Invoke(New Action(
Sub()
Label1.Text = $"{i}秒経過"
End Sub))
System.Threading.Thread.Sleep(1000)
Next
End Sub)
Label1.Text = "タスク終了"
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
mre.Set()
End Sub
End Class
タスクの実行キャンセル
Public Class Form1
Private cts As New System.Threading.CancellationTokenSource()
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim res = Await Task.Factory.StartNew(Of Boolean)(
Function()
Dim i As Integer
For i = 1 To 10
If cts.Token.IsCancellationRequested Then
Return False
End If
Me.Invoke(New Action(
Sub()
Label1.Text = $"{i}秒経過"
End Sub))
System.Threading.Thread.Sleep(1000)
Next
Return True
End Function, cts.Token)
If res Then
Label1.Text = "タスク正常終了"
Else
Label1.Text = "タスクがキャンセルされました"
End If
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
cts.Cancel()
End Sub
End Class
DB操作
IDEにDB接続
[表示]->[サーバーエクスプローラー]->[データ接続]右クリック->[接続の追加]
プロジェクトにDB接続
[プロジェクト]->[新しいデータソースの追加]
実行時DB接続
※System.sqlClient、System.Configurationを参照設定する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cs As String = ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString
Dim cn As SqlConnection = New SqlConnection(cs)
Try
cn.Open()
MessageBox.Show("接続しました", "通知")
cn.Close()
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
データベースの接続状況取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
MessageBox.Show($"接続状態：{cn.State}", "通知")
cn.Close()
MessageBox.Show($"接続状態：{cn.State}", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
テーブル名の一覧表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim schemaTable As DataTable = cn.GetSchema("Tables")
cn.Close()
ListBox1.Items.Clear()
For Each dr As DataRow In schemaTable.Rows
ListBox1.Items.Add(dr(2))
Next
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
テーブルのフィールド一覧を取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim dt As DataTable = cn.GetSchema("Columns")
cn.Close()
ListBox1.Items.Clear()
For i As Integer = 0 To dt.Rows.Count - 1
ListBox1.Items.Add(dt.Rows(i)("COLUMN_NAME").ToString())
Next
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
データベースに神機テーブル追加
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim sql As String = "drop table テスト"
Dim cm = New SqlCommand(sql, cn)
cm.ExecuteNonQuery()
MessageBox.Show("テーブル削除", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
テーブルにレコード追加
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim sql As String = "insert into 社員 values('100091','たなかはなこ','01')"
Dim cm = New SqlCommand(sql, cn)
cm.ExecuteNonQuery()
MessageBox.Show("追加", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
テーブルのレコード削除
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim sql As String = "delete from 社員 where 社員番号 = 100091"
Dim cm = New SqlCommand(sql, cn)
cm.ExecuteNonQuery()
MessageBox.Show("削除", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
テーブルのレコード参照
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim sql As String = "select * from 社員"
Dim cm = New SqlCommand(sql, cn)
Using dr = cm.ExecuteReader
ListBox1.Items.Clear()
While dr.Read()
ListBox1.Items.Add(dr.GetString(0) & "：" & dr.GetString(1))
End While
End Using
cn.Close()
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
テーブルのレコード数を取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim sql As String = "select count(*) from 社員"
Dim cmd As SqlCommand = New SqlCommand(sql, cn)
Dim num = CInt(cmd.ExecuteScalar())
cn.Close()
MessageBox.Show(num & "件のレコードがあります", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
テーブルのフィールド数を取得する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim sql As String = "select * from 社員"
Dim cmd As SqlCommand = New SqlCommand(sql, cn)
Using dr = cmd.ExecuteReader()
MessageBox.Show("フィールド数：" & dr.FieldCount, "通知")
End Using
cn.Close()
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
テーブルのフィールド名取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
cn.Open()
Dim sql As String = "select * from 社員"
Dim cmd As SqlCommand = New SqlCommand(sql, cn)
Using dr = cmd.ExecuteReader()
ListBox1.Items.Clear()
For i As Integer = 0 To dr.FieldCount - 1
ListBox1.Items.Add($"{i + 1}番目のフィールド：{dr.GetName(i)}")
Next
End Using
cn.Close()
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
データセットにデータベースのデータを取得
Dataset・・・複数の結果テーブルを扱う
DataTable ・・・一つの結果テーブルを扱う
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim ds = New DataSet("t_社員")
ad.Fill(ds, "t_社員")
MessageBox.Show("データテーブルに取得しました", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataSet
ad.Fill(dt)
MessageBox.Show("データテーブルに取得しました", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
データセットのレコードを参照
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Dim q = From r In dt
Select String.Join(" ", r.ItemArray)
ListBox1.DataSource = q.ToList()
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
データセット内のフィールドの数を取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Dim cnt = dt.Columns.Count
MessageBox.Show($"テーブルのフィールド数：{cnt}", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
データセット内のレコードの数を取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Dim cnt = dt.Rows.Count
MessageBox.Show($"テーブルのレコード数：{cnt}", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
End Class
データセットから条件に合致するデータを取得する
Public Class Form1
'条件を満たすレコードを抽出
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Try
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Dim view = New DataView(dt, "部門コード = 01", "", DataViewRowState.CurrentRows)
ListBox1.Items.Clear()
For i As Integer = 0 To view.Count - 1
Dim s = ""
For j As Integer = 0 To view.Table.Columns.Count - 1
s += view(i)(j) & " "
Next
ListBox1.Items.Add(s)
Next
Catch ex As Exception
MessageBox.Show(ex.Message, "通知")
End Try
End Sub
'LINQでレコードを抽出
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim cn As SqlConnection = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable
ad.Fill(dt)
Dim q = From t In dt
Where t("部門コード") = 1
Select String.Join(" ", t.ItemArray)
ListBox1.DataSource = q.ToList()
End Sub
End Class
データセットのレコードをフィールドの値で並べ替える
Public Class Form1
'条件を満たすレコードを抽出
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim ds = New DataSet("t_社員")
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
ad.Fill(ds, "t_社員")
Dim view = New DataView(ds.Tables("t_社員"), "", "社員番号 DESC", DataViewRowState.CurrentRows)
ListBox1.Items.Clear()
For Each v In view
ListBox1.Items.Add($"{v("社員番号")}{v("名前")}")
Next
End Sub
End Class
データセットのテーブルのフィールドの型名取得
Public Class Form1
'条件を満たすレコードを抽出
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Dim nam = dt.Columns(0).DataType.ToString()
MessageBox.Show("フィールドの型名：" + nam, "通知")
End Sub
End Class
データセットから指定行のレコード取得
Public Class Form1
'条件を満たすレコードを抽出
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Dim row = dt.Rows(2)
MessageBox.Show($"{row(0)} {row(1)}", "通知")
End Sub
End Class
データセットにテーブルを作成
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ds As New DataSet("生物")
Dim dt = ds.Tables.Add("恐竜")
dt.Columns.Add("ID", GetType(Integer))
dt.Columns.Add("名前", GetType(String))
MessageBox.Show(
$"[{ds.Tables(0).TableName}]テーブルを追加しました", "通知")
End Sub
End Class
データセットのテーブルにレコード追加
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ds = New DataSet("生物")
Dim colData = {2, "ブラキオサウルス "}
Dim dt = ds.Tables.Add("恐竜")
dt.Columns.Add("ID", GetType(Integer))
dt.Columns.Add("名前", GetType(String))
Dim row = dt.NewRow()
row("ID") = 1
row("名前") = "ティラノサウルス"
dt.Rows.Add(row)
dt.Rows.Add(colData)
MessageBox.Show("追加したレコード： " &
ds.Tables(0).Rows(0)(0) &
" " &
ds.Tables(0).Rows(0)(1), "結果通知")
End Sub
End Class
datagridviewにデータ表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
DataGridView1.DataSource = dt
End Sub
End Class
datagridviewに抽出したレコードを表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Dim view = New DataView(dt, "部門コード= 1", "", DataViewRowState.CurrentRows)
Me.DataGridView1.DataSource = view
End Sub
End Class
datagridviewに行ヘッダーを表示しない
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
DataGridView1.RowHeadersVisible = False
DataGridView1.DataSource = dt
End Sub
End Class
datagridviewの指定列を読み取り専用にする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Me.DataGridView1.DataSource = dt
Me.DataGridView1.Columns(0).ReadOnly = True
End Sub
End Class
datagridviewに行を追加不可にする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql As String = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Me.DataGridView1.AllowUserToAddRows = False
Me.DataGridView1.DataSource = dt
End Sub
End Class
datagridviewに列を作成してデータ追加
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim row1 = {"001", "ライオン"}
Dim row2 = {"002", "トラ"}
Dim row3 = {"003", "ヒョウ"}
DataGridView1.Columns.Clear()
DataGridView1.Columns.Add("No", "No.")
DataGridView1.Columns.Add("Name", "名前")
DataGridView1.Rows.Add(row1)
DataGridView1.Rows.Add(row2)
DataGridView1.Rows.Add(row3)
End Sub
End Class
datagridviewの行の編集状態を調べる
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt = DirectCast(Me.DataGridView1.DataSource, DataTable)
For i As Integer = 0 To dt.Rows.Count - 1
System.Diagnostics.Debug.WriteLine(
i.ToString() + vbTab + dt.Rows(i).RowState.ToString())
Next
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Me.DataGridView1.DataSource = dt
End Sub
End Class
datagridviewの編集状態を確定する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt = DirectCast(DataGridView1.DataSource, DataTable)
For Each dRow As DataRow In dt.Rows
If dRow.RowState <> DataRowState.Unchanged Then
dRow.AcceptChanges()
End If
Next
For i As Integer = 0 To dt.Rows.Count - 1
System.Diagnostics.Debug.WriteLine(
i & dt.Rows(i).RowState.ToString())
Next
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
Dim sql = "select * from 社員"
Dim ad = New SqlDataAdapter(sql, cn)
Dim dt = New DataTable()
ad.Fill(dt)
Me.DataGridView1.DataSource = dt
End Sub
End Class
トランザクションを開始、終了する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
cn.Open()
Dim tr = cn.BeginTransaction()
MessageBox.Show("トランザクションを開始しました", "通知")
tr.Commit()
MessageBox.Show("トランザクションを終了しました", "通知")
cn.Close()
End Sub
End Class
トランザクションを適用する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
cn.Open()
Dim cmd = cn.CreateCommand()
Dim tr = cn.BeginTransaction()
cmd.Connection = cn
cmd.Transaction = tr
cmd.CommandText = "insert into 社員 values('10101','まお','3')"
cmd.ExecuteNonQuery()
tr.Commit()
MessageBox.Show("処理を終了しました", "通知")
cn.Close()
End Sub
End Class
トランザクションを中止する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim cn = New SqlConnection(
ConfigurationManager.ConnectionStrings("_02.My.MySettings.SampleDBConnectionString").ConnectionString)
cn.Open()
Dim sql As String = "insert into 社員 values('22222','nanana','5')"
Dim cmd = New SqlCommand(sql, cn)
Dim tr = cn.BeginTransaction()
cmd.Transaction = tr
Try
cmd.ExecuteNonQuery()
tr.Commit()
MessageBox.Show("終了しました", "通知")
Catch ex As Exception
tr.Rollback()
MessageBox.Show(ex.Message, "エラー")
MessageBox.Show("ロールバックしました", "通知")
End Try
cn.Close()
End Sub
End Class
LINQ
LINQの基本
Public Class Form2
Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
Dim lst = New List(Of Control)()
For Each c As Control In Me.Controls
lst.Add(c)
Next
Dim q = From c In lst
Where TypeOf c Is Button Select c.Name
ListBox1.DataSource = q.ToList()
End Sub
End Class
LINQで配列を扱う
Public Class Form2
Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
Dim persons = {
"masuda tomoaki",
"sato eri",
"ito yui",
"masuda daiki",
"masuda yuriko"}
Dim q = From p In persons
Where p.StartsWith("masuda") Select p
ListBox1.DataSource = q.ToList()
End Sub
End Class
LINQでXMLを扱う
Public Class Form2
Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
Dim persons = XElement.Load("C:\Users\ttm11\OneDrive\デスクトップ\persons.xml")
Dim q = From p In persons.Descendants("person")
Where p.Element("name").Value.StartsWith("masuda")
Select p.Element("name").Value
ListBox1.DataSource = q.ToList()
End Sub
End Class
<persons>
<person><name>masuda tomoaki</name><age>49</age></person>
<person><name>masuda yumi</name><age>44</age></person>
<person><name>masuda kaho</name><age>13</age></person>
<person><name>masuda kazuhisa</name><age>7</age></person>
<person><name>shinohara hayato</name><age>18</age></person>
<person><name>shinohara shota</name><age>17</age></person>
</persons>
LINQでDataSetを扱う
Public Class Form2
Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
Dim ad = New DataSet1TableAdapters.社員TableAdapter()
Dim table = ad.GetData()
Dim q = From t In table Select t.名前
ListBox1.DataSource = q.ToList()
End Sub
End Class
LINQでデータを並べ替えて取得
Public Class Form2
Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
Dim ad = New DataSet1TableAdapters.社員TableAdapter()
Dim table = ad.GetData()
Dim q = From t In table Order By t.社員番号 Descending Select t.名前
ListBox1.DataSource = q.ToList()
End Sub
End Class
指定した行番号のレコードを取得する
Public Class Form2
Private Sub Button10_Click(sender As Object, e As EventArgs) Handles Button10.Click
Dim n = Integer.Parse(TextBox1.Text)
Dim ad = New DataSet1TableAdapters.社員TableAdapter()
Dim table = ad.GetData()
Dim q = From t In table Order By t.社員番号
Skip n Take 1
Select t.社員番号
ListBox1.DataSource = q.ToList()
End Sub
End Class
指定したフィールド名の値を取得する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ent = New DataSet1TableAdapters.社員TableAdapter()
Dim table = ent.GetData()
Dim q = From t In table
Select New With {t.社員番号, t.名前}
DataGridView1.DataSource = q.ToList()
End Sub
End Class
取得したレコード数を取得する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ent = New DataSet1TableAdapters.社員TableAdapter()
Dim table = ent.GetData()
Dim q = From t In table
Select t
Dim count = q.Count()
TextBox1.Text = count
End Sub
End Class
データの合計値取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ent = New DataSet1TableAdapters.社員TableAdapter()
Dim table = ent.GetData()
Dim q = From t In table
Select t.部門コード
Dim sum = q.Sum()
TextBox1.Text = sum
End Sub
End Class
リストボックスにデータバインド
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ent = New DataSet1TableAdapters.社員TableAdapter()
Dim table = ent.GetData()
Dim q = From t In table
Select t.社員番号, t.名前
ListBox1.DataSource = q.ToList()
End Sub
End Class
DataGridViewにデータバインド
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ent = New DataSet1TableAdapters.社員TableAdapter()
Dim table = ent.GetData()
Dim q = From t In table
Select t
DataGridView1.DataSource = q.ToList()
End Sub
End Class
エラー処理
構造化エラー処理
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a As Integer
Try
a = Integer.Parse("間違った値")
Catch ex As Exception
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
すべての例外処理に対処
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a As Integer
Try
a = Integer.Parse("間違った値")
Catch ex As ArgumentNullException
MessageBox.Show("引数が無効です", "エラー発生")
Catch ex As Exception
MessageBox.Show("予期しないエラーが発生しました", "エラー発生")
End Try
End Sub
End Class
例外の後処理
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a As Integer
Try
a = 10
Return
Catch ex As FormatException
MessageBox.Show(ex.Message, "エラー発生")
Finally
MessageBox.Show("Finallyブロックの処理", "通知")
End Try
End Sub
End Class
例外のメッセージ取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a As Integer
Try
a = Integer.Parse("間違った値")
Catch ex As Exception
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
配列のインデックスが範囲外の例外
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ary = {1, 2, 3}
Try
Dim num = ary(5)
Catch ex As IndexOutOfRangeException
MessageBox.Show(ex.Message, "エラー")
End Try
End Sub
End Class
無効なメソッドの呼び出しの例外
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim s = ""
Try
System.Diagnostics.Process.Start(s)
Catch ex As InvalidOperationException
MessageBox.Show(ex.Message, "エラー")
End Try
End Sub
End Class
例外を呼び出し元で処理
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
SampleProc()
Catch ex As Exception
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
Private Sub SampleProc()
Dim a As Integer
a = Integer.Parse("間違った値")
MessageBox.Show($"a = {a}", "通知")
End Sub
End Class
例外の種類を取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a As Integer
Try
a = Integer.Parse("間違った値")
Catch ex As Exception
MessageBox.Show(ex.GetType().ToString(), "エラー発生")
End Try
End Sub
End Class
例外が発生した場所を取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a = 0
Try
a = Integer.Parse("間違った値")
Catch ex As Exception
MessageBox.Show(ex.StackTrace, "エラー発生")
End Try
End Sub
End Class
例外を発生させる
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a = 10
Dim b = 0
Try
If b = 0 Then
Throw New DivideByZeroException("0では除算できません")
End If
a = a / b
MessageBox.Show($"a = {a}", "通知")
Catch ex As Exception
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
新しい例外を定義
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim a = 10
Dim b = 0
Try
If b = 0 Then
Throw New SampleException("0による除算はできません")
End If
a = a / b
Catch ex As Exception
MessageBox.Show(ex.Message, "エラー")
End Try
End Sub
End Class
Public Class SampleException
Inherits Exception
Public Sub New()
MyBase.New()
End Sub
Public Sub New(msg As String)
MyBase.New(msg)
End Sub
Public Sub New(msg As String, inner As Exception)
MyBase.New(msg, inner)
End Sub
End Class
引数が無効の場合の例外
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim s = ""
Try
Label1.Text = Integer.Parse(s).ToString()
Catch ex As FormatException
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
引数の値が範囲外の場合の例外
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim s = "Sample"
Try
Label1.Text = s.Substring(7, 2)
Catch ex As ArgumentOutOfRangeException
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
引数がNothingの場合の例外
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim s1 = "abc"
Dim s2 = Nothing
Try
Label1.Text = s1.Insert(2, s2)
Catch ex As ArgumentNullException
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
IOエラーが発生した場合の例外
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dname As String = "C:\VB2017\Sample.txt"
Try
For Each fname In System.IO.Directory.GetFiles(dname)
ListBox1.Items.Add(fname)
Next
Catch ex As System.IO.IOException
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
ファイルが存在しない場合の例外
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
Dim img = Image.FromFile("C:1111.jbg")
Catch ex As System.IO.FileNotFoundException
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
フォルダーが存在しない場合の例外
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
For Each fname In System.IO.Directory.GetFiles("C:\aaa")
ListBox1.Items.Add(fname)
Next
Catch ex As System.IO.DirectoryNotFoundException
MessageBox.Show(ex.Message, "エラー発生")
End Try
End Sub
End Class
コモンダイアログ
ファイルを開くダイアログ
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
With OpenFileDialog1
.Title = "画像ファイルの選択"
.CheckFileExists = True
.RestoreDirectory = True
.Filter = "イメージファイル|*.bmp;*.jpg;*.gif"
End With
If OpenFileDialog1.ShowDialog() = DialogResult.OK Then
Label1.Text = OpenFileDialog1.FileName
Label2.Text = OpenFileDialog1.SafeFileName
PictureBox1.Image = Image.FromFile(OpenFileDialog1.FileName)
Else
Label1.Text = ""
Label2.Text = ""
PictureBox1.Image = Nothing
End If
End Sub
End Class
名前を付けて保存するダイアログ
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
With SaveFileDialog1
.RestoreDirectory = True
.OverwritePrompt = True
.Filter = "JPeg(*.jpg)|*.jpg|Gif(*.gif)|*.gif"
End With
If SaveFileDialog1.ShowDialog() = DialogResult.Cancel Then
Return
End If
Label1.Text = Path.GetFileName(SaveFileDialog1.FileName)
Using fs = DirectCast(SaveFileDialog1.OpenFile(), FileStream)
If SaveFileDialog1.FilterIndex = 1 Then
PictureBox1.Image.Save(fs, Imaging.ImageFormat.Jpeg)
Else
PictureBox1.Image.Save(fs, Imaging.ImageFormat.Gif)
End If
End Using
Label1.Text = "保存しました"
End Sub
End Class
フォントを設定するダイアログボックスを表示する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
With FontDialog1
.ShowColor = True
.Font = RichTextBox1.SelectionFont
.Color = RichTextBox1.SelectionColor
End With
If FontDialog1.ShowDialog() = DialogResult.OK Then
With RichTextBox1
.SelectionFont = FontDialog1.Font
.SelectionColor = FontDialog1.Color
End With
End If
End Sub
End Class
色を設定するダイアログ
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If ColorDialog1.ShowDialog() = DialogResult.OK Then
Label1.BackColor = ColorDialog1.Color
End If
End Sub
End Class
フォルダーを選択するダイアログ
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
FolderBrowserDialog1.Description = "フォルダーを選択してください"
FolderBrowserDialog1.ShowNewFolderButton = False
If FolderBrowserDialog1.ShowDialog() = DialogResult.OK Then
Label1.Text = FolderBrowserDialog1.SelectedPath
Else
Label1.Text = ""
End If
End Sub
End Class
文字列操作
文字コード取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim code = Asc("A")
Label1.Text = code.ToString()
End Sub
End Class
文字の長さ取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text = TextBox1.Text
Label1.Text = text.Length.ToString()
End Sub
End Class
大文字を小文字にする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text = TextBox1.Text
Label1.Text = text.ToUpper()
Label2.Text = text.ToLower()
End Sub
End Class
指定位置から指定文字数分の文字を取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text As String = TextBox1.Text
Label1.Text = ""
If text.Length < 7 Then
MessageBox.Show("7文字以上入力してください", "通知")
Return
End If
Label1.Text = text.Substring(4, 3)
End Sub
End Class
文字列内に指定した文字列が存在するか調べる
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If TextBox1.Text.Contains("リス") = True Then
Label1.Text = "含まれています"
Else
Label1.Text = "含まれていません"
End If
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If RegexStringValidator.Equals(TextBox1.Text, "ク*マ") Then
Label1.Text = "含まれています"
Else
Label1.Text = "含まれていません"
End If
End Sub
End Class
文字列内から指定した文字列の位置を検索
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text = TextBox1.Text
Dim pos = -1
ListBox1.Items.Clear()
While True
pos = text.IndexOf("カキ", pos + 1)
If pos = -1 Then
Exit While
End If
ListBox1.Items.Add((pos + 1) & "文字目")
End While
End Sub
End Class
2つの文字列の大小を比較
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text1 = TextBox1.Text
Dim text2 = TextBox2.Text
Dim ret = text1.CompareTo(text2)
If ret = 0 Then
Label1.Text = "同じです"
ElseIf ret < 0 Then
Label1.Text = text1 & "の方が小さいです"
Else
Label2.Text = text1 & "の方が大きいです"
End If
End Sub
End Class
文字列内の指定文字を別の文字に置き換える
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text1 = TextBox1.Text
Label2.Text = text1.Replace("し", "シ")
End Sub
End Class
文字列が指定文字列で始まっているか調べる
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text1 = TextBox1.Text
If text1.StartsWith("My") Then
Label1.Text = "Myで始まっています"
Else
Label1.Text = "Myで始まっていません"
End If
End Sub
End Class
文字列の前後のスペースを削除する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim t = TextBox1.Text
If t = String.Empty Then
Return
End If
Label1.Text = "「" + t.Trim() + "」"
Label2.Text = "「" + t.TrimStart() + "」"
Label3.Text = "「" + t.TrimEnd() + "」"
End Sub
End Class
文字列内から指定位置の文字を削除
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text1 = TextBox1.Text
Dim text2 = TextBox2.Text
If text1.Length < 4 Then
MessageBox.Show("4文字以上入力してください", "通知")
Return
End If
Label1.Text = text1.Remove(1, 3)
End Sub
End Class
文字列内に別の文字列を挿入する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text1 = TextBox1.Text
Dim text2 = TextBox2.Text
If text1.Length < 2 Then
Return
End If
Label1.Text = text1.Insert(2, text2)
End Sub
End Class
文字列が指定した文字数になるまでスペースを入れる
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim Text1 = TextBox1.Text
Label1.Text = "「" + Text1.PadLeft(15) + "」"
Label2.Text = "「" + Text1.PadRight(15) + "」"
End Sub
End Class
文字列を指定した区切り文字で分割する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim text1 As String = TextBox1.Text
Dim textArray = text1.Split("/"c)
ListBox1.Items.Clear()
For Each text2 As String In textArray
ListBox1.Items.Add(text2)
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim text1 As String = TextBox1.Text
Dim textArray = text1.Split({"/"}, StringSplitOptions.None)
ListBox1.Items.Clear()
For Each text2 As String In textArray
ListBox1.Items.Add(text2)
Next
End Sub
End Class
文字列配列の各要素を連結する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim textArray = {"aaa", "bbb", "ccc"}
Dim mark = TextBox1.Text
Label1.Text = String.Join(mark, textArray)
End Sub
End Class
数値と日付の書式を指定する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim num = 10.12345
Dim myData = DateTime.Now
Label1.Text = myData.ToString("yy/MM/dd(ddd) HH:mm:ss")
Label2.Text = myData.ToString("tt h:m:s")
Label3.Text = myData.ToString("D")
Label4.Text = num.ToString("000.000")
Label5.Text = num.ToString("0.00%")
Label6.Text = num.ToString("#.#")
Label7.Text = num.ToString("C")
Label8.Text = num.ToString("P")
End Sub
End Class
ユーザーインターフェース
フォームのサイズを固定
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.FormBorderStyle = FormBorderStyle.FixedToolWindow
Label1.Text = "fixedtoolwindow"
End Sub
End Class
最大化・最小化ボタンを非表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If Me.MaximizeBox = True And Me.MinimizeBox = True Then
Me.MaximizeBox = False
Me.MinimizeBox = False
Else
Me.MaximizeBox = True
Me.MinimizeBox = True
End If
End Sub
End Class
ヘルプボタン表示
[プロパティウィンドウで操作]
１、最大化・最小化ボタンを非表示にする
２、ヘルプボタンを表示する
３、イベントの「HelpRequested」をダブルクリック
Public Class Form1
Private Sub Form1_HelpRequested(sender As Object, hlpevent As HelpEventArgs) Handles MyBase.HelpRequested
MessageBox.Show("ボタンをクリックすると終了します。")
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.Close()
End Sub
End Class
フォームをモニターの大きさに合わせる
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.WindowState = FormWindowState.Maximized
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.WindowState = FormWindowState.Normal
End Sub
End Class
フォームを表示する/閉じる
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim newForm As New Form3
newForm.Label1.Text = "モーダルで表示しています"
newForm.ShowDialog()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim newForm As New Form3
newForm.Label1.Text = "モードレスで表示しています"
newForm.Show()
End Sub
End Class
Public Class Form3
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.Close()
End Sub
End Class
フォームの表示位置を指定
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim newForm As New Form3
newForm.StartPosition = FormStartPosition.Manual
newForm.Location = New Point(0, 0)
newForm.Show()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim newForm As New Form3
newForm.StartPosition = FormStartPosition.CenterScreen
newForm.Show()
End Sub
End Class
フォームの大きさを変更
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.Width += 10
Me.Height += 10
End Sub
End Class
デフォルトボタン、キャンセルボタン設定
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
MessageBox.Show("[OK]ボタンがクリックされました", "結果")
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
MessageBox.Show("[キャンセル]します", "結果")
Me.Close()
End Sub
End Class
フォームやコントロールの初期設定
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.AcceptButton = Button1
Me.CancelButton = Button2
Label1.Text = "初期設定"
Button1.Text = "OK"
Button2.Text = "Cancel"
End Sub
End Class
フォームを半透明にする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.Opacity -= 0.1
End Sub
End Class
ほかのフォームのコントロールの値を参照
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim newForm As New Form3
newForm.ShowDialog()
Label1.Text = newForm.TextBox1.Text
End Sub
End Class
ダイアログボックスでクリックされた結果をフォームで取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Label1.Text = ""
Dialog1.ShowDialog()
Select Case Dialog1.DialogResult
Case DialogResult.OK
Label1.Text = "OK"
Case DialogResult.Cancel
Label1.Text = "Cancel"
End Select
End Sub
End Class
任意に位置に文字列を表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Label1.AutoSize = False
Label1.Size = New Size(300, 40)
Label1.Text = "現在の日時：" + DateTime.Now.ToString()
Label1.ForeColor = Color.DarkBlue
Label1.BorderStyle = BorderStyle.FixedSingle
Label1.TextAlign = ContentAlignment.MiddleCenter
End Sub
End Class
リンクラベルでWEBページにリンクする
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
LinkLabel1.Text = "サイトを開きます"
LinkLabel1.Links.Add(0, 3, "www.shuwasystem.co.jp")
End Sub
Private Sub LinkLabel1_LinkClicked(sender As Object, e As LinkLabelLinkClickedEventArgs) Handles LinkLabel1.LinkClicked
Dim linkTarget As String
linkTarget = LinkLabel1.Links(0).LinkData.ToString()
System.Diagnostics.Process.Start(linkTarget)
LinkLabel1.LinkVisited = True
End Sub
End Class
リンクラベルで別のフォームにリンクする
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
LinkLabel1.Text = "別のフォームを開きます"
LinkLabel1.LinkArea = New LinkArea(2, 4)
End Sub
Private Sub LinkLabel1_LinkClicked(sender As Object, e As LinkLabelLinkClickedEventArgs) Handles LinkLabel1.LinkClicked
Form3.ShowDialog()
LinkLabel1.LinkVisited = True
End Sub
End Class
ボタンを使う
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
MessageBox.Show("ボタンがクリックされました", "結果")
End Sub
End Class
テキストボックスで文字の入力を取得する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
MessageBox.Show("入力内容" + TextBox1.Text, "結果")
End Sub
End Class
入力する文字の種類を指定する
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
TextBox1.ImeMode = ImeMode.Off
TextBox2.ImeMode = ImeMode.On
End Sub
End Class
テキストボックスを読み取り専用にする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.ReadOnly = True
TextBox2.Enabled = False
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
TextBox1.ReadOnly = False
TextBox2.Enabled = True
End Sub
End Class
入力できる文字数を制限
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If TextBox1.Text.Length < 4 Then
Label1.Text = TextBox1.Text.Length.ToString & "・・・文字数が足りません"
Else
Label1.Text = TextBox1.Text.Length.ToString
End If
End Sub
End Class
テキストボックスに指定した形式でデータを入力
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If MaskedTextBox1.MaskCompleted Then
If IsDate(MaskedTextBox1.Text) Then
Label1.Text = MaskedTextBox1.Text
Else
Label1.Text = "正確に入力してください"
MaskedTextBox1.Clear()
End If
Else
Label1.Text = "最後まで入力してください"
End If
End Sub
End Class
複数選択できる選択肢を設ける
Public Class Form1
Dim a1 As Integer = 1000
Dim a2 As Integer = 500
Dim a3 As Integer = 10
Dim a4 As Integer = 5
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim sum As Integer = 0
If CheckBox1.Checked Then
sum += a1
End If
If CheckBox2.Checked Then
sum += a2
End If
If CheckBox3.Checked Then
sum += a3
End If
If CheckBox4.Checked Then
sum += a4
End If
Label1.Text = sum.ToString("#,###円")
End Sub
End Class
１つだけ選択できる選択肢を設ける
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myString As String
If RadioButton1.Checked Then
myString = RadioButton1.Text
ElseIf RadioButton2.Checked Then
myString = RadioButton2.Text
End If
Label1.Text = myString
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
RadioButton1.Checked = True
End Sub
End Class
ラジオボタンのリストをスクロールする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myRB As RadioButton
For Each myRB In Panel1.Controls
If myRB.Checked Then
Label1.Text = myRB.Text
Exit For
End If
Next
End Sub
End Class
グループごとに1つだけ選択できるようにする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myRB As RadioButton
Dim myText As String
For Each myRB In GroupBox2.Controls
If myRB.Checked Then
myText = myRB.Text
Exit For
End If
Next
Label1.Text = myText
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
RadioButton1.Checked = True
End Sub
End Class
ピクチャーボックスに画像を表示・非表示にする
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If CheckBox1.Checked Then
PictureBox1.Image = Image.FromFile("C:\Users\aaa.jpg")
PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
Else
PictureBox1.Image.Dispose()
PictureBox1.Image = Nothing
End If
End Sub
End Class
ピクチャーボックスに画像を重ねて表示する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If CheckBox1.Checked Then
PictureBox1.Image = Image.FromFile("C:\Users\aaa.jpg")
PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
Else
PictureBox1.Image.Dispose()
PictureBox1.Image = Nothing
End If
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
PictureBox1.BackgroundImage = Image.FromFile("C:\Users\bbb.jpg")
PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
End Sub
End Class
リストボックスに項目を追加、削除する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myArray() As String = {"ホワイト", "イエロー", "ブルー"}
ListBox1.Items.Clear()
ListBox1.Items.AddRange(myArray)
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If ListBox1.Items.Count <> 0 Then
ListBox1.Items.RemoveAt(0)
End If
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
If ListBox1.Items.Count <> 0 Then
ListBox1.Items.RemoveAt(ListBox1.Items.Count - 1)
End If
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ListBox1.Items.Add("ホワイト")
ListBox1.Items.Add("イエロー")
ListBox1.Items.Add("ブルー")
End Sub
End Class
リストボックスに順番を指定して項目を追加
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If TextBox1.Text <> "" Then
ListBox1.Items.Insert(0, TextBox1.Text)
TextBox1.Text = ""
End If
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If TextBox1.Text <> "" Then
ListBox1.Items.Insert(ListBox1.Items.Count, TextBox1.Text)
TextBox1.Text = ""
End If
End Sub
End Class
リストボックスで項目を選択し、その項目を取得する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If ListBox1.SelectedIndex = -1 Then
Label1.Text = "選択されていません"
Else
Label1.Text = ListBox1.SelectedIndex + 1 & "番目: " & ListBox1.SelectedItem
End If
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
ListBox1.ClearSelected()
Label1.Text = ""
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ListBox1.SelectedIndex = 0
End Sub
End Class
リストボックスで複数選択された項目を取得
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myList As Object
For Each myList In ListBox1.SelectedItems
ListBox2.Items.Add(myList)
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim i As Integer
For i = ListBox1.Items.Count - 1 To 0 Step -1
If ListBox1.GetSelected(i) Then
ListBox1.Items.RemoveAt(i)
End If
Next
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim myArray() As String = {"A4用紙", "ペン", "消しゴム", "ファイル", "ノート", "のり"}
ListBox1.Items.AddRange(myArray)
ListBox1.SelectionMode = SelectionMode.MultiSimple
ListBox2.SelectionMode = SelectionMode.MultiSimple
End Sub
End Class
チェックボックス付きリストボックス
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myItem As Object
ListBox1.Items.Clear()
For Each myItem In CheckedListBox1.CheckedItems
ListBox1.Items.Add(myItem)
Next
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim myArray() As String = {"アジア", "オセアニア", "アメリカ", "ヨーロッパ", "アフリカ"}
CheckedListBox1.Items.AddRange(myArray)
CheckedListBox1.SetItemChecked(0, True)
End Sub
End Class
コンボボックス
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If ComboBox2.SelectedIndex = -1 Then
Label1.Text = "選択されていません"
Else
Label1.Text = ComboBox2.Text
End If
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ComboBox2.Items.Add("イチゴパフェ")
ComboBox2.Items.Add("バナナアイス")
ComboBox2.Items.Add("フォンダンショコラ")
ComboBox2.Items.Add("パンケーキ")
End Sub
End Class
タブコントロール
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myTP As TabPage
Dim myRB As RadioButton
ListBox1.Items.Clear()
For Each myTP In TabControl1.TabPages
For Each myRB In myTP.Controls
If myRB.Checked Then
ListBox1.Items.Add(myRB.Text)
End If
Next
Next
End Sub
End Class
カレンダーで日付選択
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
TextBox1.Text = DateTimePicker1.Value.ToShortDateString
TextBox2.Text = DateTimePicker1.Value
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
DateTimePicker1.Format = DateTimePickerFormat.Long
DateTimePicker1.Value = DateTime.Now
DateTimePicker1.MinDate = #1/1/1960#
DateTimePicker1.MaxDate = #12/31/2020#
End Sub
End Class
日付範囲を選択できるカレンダー
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim startDay As DateTime = MonthCalendar1.SelectionStart
Dim endDay As DateTime = MonthCalendar1.SelectionEnd
Label1.Text = startDay.ToLongTimeString
Label2.Text = endDay.ToLongTimeString
Label3.Text = endDay.Subtract(startDay).Days - 1
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
MonthCalendar1.MaxSelectionCount = 15
End Sub
End Class
タイマー
Public Class Form1
Dim startTime As New TimeSpan(0, 0, 0)
Dim addSecond As New TimeSpan(0, 0, 1)
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Timer1.Enabled = Not Timer1.Enabled
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Timer1.Enabled = False
startTime = New TimeSpan(0, 0, 0)
Label1.Text = startTime.ToString
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
startTime = startTime + addSecond
Label1.Text = startTime.ToString()
If startTime = New TimeSpan(3, 0, 0) Then
Timer1.Stop()
End If
End Sub
End Class
メニューバーを作成
Public Class Form1
Private Sub 左揃えToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 左揃えToolStripMenuItem.Click
TextBox1.TextAlign = HorizontalAlignment.Left
End Sub
Private Sub 右揃えToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 右揃えToolStripMenuItem.Click
TextBox1.TextAlign = HorizontalAlignment.Right
End Sub
Private Sub 中央揃えToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 中央揃えToolStripMenuItem.Click
TextBox1.TextAlign = HorizontalAlignment.Center
End Sub
End Class
メニューコマンドを無効にする
Public Class Form1
Private Sub 中央揃えToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 中央揃えToolStripMenuItem.Click
TextBox1.TextAlign = HorizontalAlignment.Center
左揃えToolStripMenuItem.Enabled = True
右揃えToolStripMenuItem.Enabled = True
中央揃えToolStripMenuItem.Enabled = False
End Sub
End Class
メニューコマンドにチェックマークを付ける
Public Class Form1
Dim futoji As FontStyle
Dim syatai As FontStyle
Private Sub 太字ToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 太字ToolStripMenuItem.Click
If 太字ToolStripMenuItem.Checked Then
futoji = FontStyle.Regular
太字ToolStripMenuItem.Checked = False
Else
futoji = FontStyle.Bold
太字ToolStripMenuItem.Checked = True
End If
TextBox1.Font = New Font(TextBox1.Font, futoji + syatai)
End Sub
Private Sub 斜体ToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 斜体ToolStripMenuItem.Click
If 斜体ToolStripMenuItem.Checked Then
syatai = FontStyle.Regular
斜体ToolStripMenuItem.Checked = False
Else
syatai = FontStyle.Italic
斜体ToolStripMenuItem.Checked = True
End If
TextBox1.Font = New Font(TextBox1.Font, futoji + syatai)
End Sub
End Class
ショートカットキーを割り当てる
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
太字ToolStripMenuItem.ShortcutKeys = Keys.Control Or Keys.B
End Sub
End Class
ショートカットメニューをつける
Public Class Form1
Private Sub 中央揃えToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles 中央揃えToolStripMenuItem.Click
Dim obj As TextBox = ContextMenuStrip1.SourceControl
obj.TextAlign = HorizontalAlignment.Center
End Sub
End Class
ツールバー作成
Public Class Form1
Private Sub ToolStripButton1_Click(sender As Object, e As EventArgs) Handles ToolStripButton1.Click
Dim obj As Object
For Each obj In Me.Controls
If TypeOf obj Is TextBox AndAlso TryCast(obj, TextBox).Focused Then
Dim objText = TryCast(obj, TextBox)
objText.Font = New Font(objText.Font, FontStyle.Bold)
End If
Next
End Sub
End Class
ステータスバーを作成する
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ToolStripStatusLabel1.Text = Today.ToShortDateString
End Sub
End Class
プログレスバー
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ProgressBar1.Minimum = 0
ProgressBar1.Maximum = 100000
ProgressBar1.Value = 0
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim i As Long
For i = 0 To 1000000
ProgressBar1.Value = 1
Next
Label1.Text = "処理は終了しました"
End Sub
End Class
階層構造表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Label1.Text = TreeView1.SelectedNode.FullPath
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim myNode As TreeNode = TreeView1.SelectedNode
If TextBox1.Text = "" Then Exit Sub
If myNode Is Nothing Then
MessageBox.Show("項目を選択してください", "通知")
Exit Sub
End If
myNode.Nodes.Add(New TreeNode(TextBox1.Text))
End Sub
End Class
リストビューにファイル一覧を表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dirInfo As System.IO.DirectoryInfo
Dim fileList() As System.IO.FileInfo
Dim fileInfo As System.IO.FileInfo
ListView1.Items.Clear()
If System.IO.Directory.Exists(TextBox1.Text) = False Then
MessageBox.Show("フォルダーが存在しません", "通知")
Exit Sub
End If
dirInfo = New System.IO.DirectoryInfo(TextBox1.Text)
fileList = dirInfo.GetFiles
For Each fileInfo In fileList
Dim fileItem As ListViewItem = New ListViewItem(fileInfo.Name)
fileItem.SubItems.Add(fileInfo.Length.ToString)
fileItem.SubItems.Add(fileInfo.LastWriteTime)
ListView1.Items.Add(fileItem)
Next
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ListView1.Clear()
ListView1.View = View.Details
ListView1.Columns.Add("ファイル名", 100)
ListView1.Columns.Add("ファイルサイズ", 60, HorizontalAlignment.Right)
ListView1.Columns.Add("更新日", 120)
End Sub
End Class
リストビューに画像一覧を表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim i As Integer
Dim myPath As String = "C:\Users\ttm11\OneDrive\画像\カメラ ロール"
Dim imgFile() As String = System.IO.Directory.GetFiles(myPath, "*.jpg")
For i = 0 To imgFile.Length - 1
Dim myImg As Image = Image.FromFile(imgFile(i))
ImageList1.Images.Add(myImg)
ListView1.Items.Add(imgFile(i), i)
myImg.Dispose()
Next
End Sub
End Class
リッチテキストボックスの編集を元に戻す
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim ans As Integer
Label1.Text = RichTextBox2.UndoActionName
ans = MessageBox.Show("処理を戻しますか", "確認", MessageBoxButtons.YesNo)
If ans = DialogResult.Yes Then
RichTextBox2.Undo()
End If
Label1.Text = ""
End Sub
End Class
リッチテキストボックスのフォントと色を設定する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
RichTextBox2.SelectionFont = New Font("MS ゴシック", FontStyle.Italic)
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If RichTextBox2.SelectionColor <> Color.Red Then
RichTextBox2.SelectionColor = Color.Red
Else
RichTextBox2.SelectionColor = Color.Black
End If
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim myFont As Font = RichTextBox2.SelectionFont
Dim myFS As FontStyle
If RichTextBox2.SelectionFont.Bold = False Then
myFS = FontStyle.Bold
Else
myFS = FontStyle.Regular
End If
RichTextBox2.SelectionFont = New Font(myFont.FontFamily, myFont.Size, myFS)
End Sub
End Class
リッチテキストボックスの文字を検出
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim pos As Integer
RichTextBox2.SelectionStart = RichTextBox1.SelectionStart +
RichTextBox2.SelectionLength
RichTextBox2.SelectionLength = 0
RichTextBox2.Focus()
pos = RichTextBox2.Find(TextBox1.Text, RichTextBox2.SelectionStart, RichTextBoxFinds.None)
End Sub
End Class
リッチテキストボックスにファイルの内容を表示
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If System.IO.File.Exists(TextBox1.Text) = False Then
MessageBox.Show("ファイルが存在してません", "通知")
Exit Sub
End If
If TextBox1.Text.EndsWith("txt") Then
RichTextBox2.LoadFile(TextBox1.Text, RichTextBoxStreamType.PlainText)
ElseIf TextBox1.Text.EndsWith("rtf") Then
RichTextBox2.LoadFile(TextBox1.Text, RichTextBoxStreamType.RichText)
Else
MessageBox.Show("形式が違います", "通知")
End If
End Sub
End Class
リッチテキストボックスの内容をファイルに保存する
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If System.IO.Directory.Exists(TextBox1.Text) = False Then
MessageBox.Show("フォルダーが存在しません", "通知")
Exit Sub
End If
If TextBox1.Text = "" Then
MessageBox.Show("ファイル名を選択してください", "通知")
End If
RichTextBox2.SaveFile(TextBox1.Text & "\" & TextBox2.Text & ".rtf", RichTextBoxStreamType.RichText)
MessageBox.Show("ファイルを保存しました", "結果")
End Sub
End Class
スピンボタンで数値を入力
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
NumericUpDown1.Minimum = 1
NumericUpDown1.Maximum = 100
NumericUpDown1.Value = 50
NumericUpDown1.Increment = 5
End Sub
End Class
ドラッグで数値変更
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
TrackBar1.Minimum = 10
TrackBar1.Maximum = 30
TrackBar1.Value = 10
TrackBar1.TickFrequency = 1
TrackBar1.SmallChange = 1
TrackBar1.LargeChange = 5
End Sub
Private Sub TrackBar1_Scroll(sender As Object, e As EventArgs) Handles TrackBar1.Scroll
TextBox1.Text = TrackBar1.Value.ToString()
Dim myFont As Font = Label1.Font
Label1.Font = New Font(myFont.FontFamily, TrackBar1.Value)
End Sub
End Class
パネル上のコントロールを順に参照
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim panelItem As Object
For Each panelItem In Panel1.Controls
panelItem.text = panelItem.GetType.Name
Next
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Dim panelItem As Object
For Each panelItem In Panel1.Controls
panelItem.text = ""
Next
End Sub
End Class