エクスポート

「Exporting to text in xojo」
https://stackoverflow.com/questions/49976204/exporting-to-text-in-xojo
を参考に

ListBox1.AddRow("1", "ThunderBlade", "SEGA")
ListBox1.AddRow("2", "GALAXY FORCE", "SEGA")
ListBox1.AddRow("3", "STARBLADE", "namco")
ListBox1.AddRow("4", "DARIUS", "TAITO")

Dim f As FolderItem
Dim outcsv As TextOutputStream
Var dir As New FolderItem("/mnt", FolderItem.PathModes.Native)
f = dir.Child("itemm.txt")
outcsv = f.CreateTextFile
Dim maxRow As Integer = Listbox1.ListCount - 1
For row As Integer =  0 To maxRow
  outcsv.WriteLine(""""+ListBox1.Cell(row, 0)+""","""+ListBox1.Cell(row, 1)+""","""+ListBox1.Cell(row, 2)+""","""+ListBox1.Cell(row, 3)+"""")
Next
outcsv.Close

これはデスクトップアプリ。Webアプリの場合は Listbox1.ListCount の代わりに Listbox1.RowCount を使う。

インポート

ListBoxにインポート

「TextInputStream.ReadLine」
https://docs.xojo.com/TextInputStream.ReadLine を参考

Var f As FolderItem
Var csvFile As TextInputStream
Var csvRow As String

f = FolderItem.ShowOpenFileDialog("")
If f <> Nil Then
  csvFile = TextInputStream.Open(f)
  csvFile.Encoding = Encodings.UTF8
  Do
    csvRow = csvFile.ReadLine
    Listbox1.AddRow( NthField(csvRow,",",1).ReplaceALL("""",""), NthField(csvRow,",",2).ReplaceALL("""",""), NthField(csvRow,",",3).ReplaceALL("""",""))
  Loop Until csvFile.EndOfFile
  csvFile.Close
End If

なお、 元にした
「TextInputStream.ReadLine」
https://docs.xojo.com/TextInputStream.ReadLine
では、タブ区切りファイルをインポート、更に動的にListBoxのカラム数を増やしている。

配列にインポート

ListBoxに読み込むのは遅い。上を RaspberryPi Model 3 で試してみたら7カラムx1000件の場合で10秒程度。
配列に読めば早い。

Var f As FolderItem
Var csvFile As TextInputStream
Var csvRow As String
Var regends(0, 10) As String
var counter as Integer = 0

f = FolderItem.ShowOpenFileDialog("")
If f <> Nil Then
  csvFile = TextInputStream.Open(f)
  csvFile.Encoding = Encodings.UTF8
  Do
    regends.ResizeTo(counter,10)
    csvRow = csvFile.ReadLine
    csvRow = csvFile.ReadLine
    regends(counter,1)=NthField(csvRow,",",1).ReplaceALL("""","")
    regends(counter,2)=NthField(csvRow,",",2).ReplaceALL("""","")
    regends(counter,3)=NthField(csvRow,",",3).ReplaceALL("""","")
    counter=counter+1
  Loop Until csvFile.EndOfFile
  csvFile.Close
End If