C# - RichTextBox関連やりたいこと逆引きリファレンス【自分用】 - Qiita
上記の集大成（？）です。
画面キャプチャ
サンプルコード
全角空白だらけにすると、かなり動作が重い
using System;
using System.Drawing;
using System.Text;
using System.Text.RegularExpressions;
using System.Runtime.InteropServices;
using System.Windows.Forms;
internal class MyRichTextBox:RichTextBox
{
private const Int32 WM_PAINT = 0x000F;
private static readonly int adjX = -2;
private static readonly int adjY = 2;
private int lineHeight;
private RichTextBox dummyRichTextBox; // lineHeight算出用
//----------------------------------------------------------------
// Win32
//
private const int EM_SETTABSTOPS = 0x00CB;
private const long IMF_DUALFONT = 0x80;
private const int WM_SETREDRAW = 0x0008;
private const int WM_USER = 0x0400;
private const int EM_SETLANGOPTIONS = WM_USER + 120;
private const int EM_GETLANGOPTIONS = WM_USER + 121;
private const int EM_GETTEXTEX = (WM_USER + 94);
private const int EM_GETTEXTLENGTHEX = (WM_USER + 95);
// Flags for the GETEXTEX data structure
private const int GT_DEFAULT = 0;
private const int GTL_CLOSE = 4; // Fast computation of a "close" answer
private const int GTL_DEFAULT = 0; // Do default (return # of chars)
class NativeMethods
{
[DllImport("user32.dll", EntryPoint = "SendMessage", CharSet = CharSet.Auto)]
public extern static IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, IntPtr lParam);
[DllImport("user32.dll", EntryPoint = "SendMessage", CharSet = CharSet.Auto)]
public static extern IntPtr SendMessage(IntPtr hWnd, int msg, ref GETTEXTEX wParam, StringBuilder lParam);
[DllImport("user32.dll", EntryPoint = "SendMessage", CharSet = CharSet.Auto)]
public static extern IntPtr SendMessage(IntPtr hWnd, int msg, ref GETTEXTLENGTHEX wParam, IntPtr lParam);
}
[StructLayout(LayoutKind.Sequential)]
struct GETTEXTEX
{
public int cb;
public int flags;
public int codepage;
public IntPtr lpDefaultChar;
public IntPtr lpUsedDefChar;
}
[StructLayout(LayoutKind.Sequential)]
struct GETTEXTLENGTHEX
{
public int flags;
public int codepage;
}
//
//----------------------------------------------------------------
private void EnsureDummyRichTextBox(bool forceSetFont)
{
if ( dummyRichTextBox == null ) {
dummyRichTextBox = new RichTextBox();
dummyRichTextBox.Text = "\n";
dummyRichTextBox.Font = this.Font;
}
else if ( forceSetFont ) {
dummyRichTextBox.Font = this.Font;
}
}
void RecalcLineHeight(bool fontUpdated)
{
EnsureDummyRichTextBox(fontUpdated);
int y1 = dummyRichTextBox.GetPositionFromCharIndex(dummyRichTextBox.GetFirstCharIndexFromLine(0)).Y;
int y2 = dummyRichTextBox.GetPositionFromCharIndex(dummyRichTextBox.GetFirstCharIndexFromLine(1)).Y;
lineHeight = y2 - y1;
}
protected override void OnFontChanged(EventArgs e)
{
RecalcLineHeight(true);
SetFixFont();
SetTabStop(4);
}
protected override void WndProc(ref System.Windows.Forms.Message m)
{
base.WndProc(ref m);
if ( m.Msg == WM_PAINT ) {
RecalcLineHeight(false);
using ( Graphics graphic = base.CreateGraphics() ) {
OnPaint(new PaintEventArgs(graphic, base.ClientRectangle));
}
}
}
protected override void OnPaint(PaintEventArgs pe)
{
Brush brush = Brushes.LightGray;
string s = this.Text;
int sLen = s.Length;//this.TextLength;
Graphics g = pe.Graphics;
int lineStartI = GetLineFromCharIndex(GetCharIndexFromPosition(new Point(0, 0)));
int lineEndI = GetLineFromCharIndex(GetCharIndexFromPosition(new Point(pe.ClipRectangle.Width, pe.ClipRectangle.Height)));
Regex regex = new Regex(@"[\t \r\n]"); // tab or 全角空白 or 改行
// 行ごとに処理
int nextCharI = -1;
for ( int lineI = lineStartI; lineI <= lineEndI; lineI++ ) {
int startCharI;
if ( lineI == lineStartI ) {
startCharI = GetFirstCharIndexFromLine(lineI);
}
else {
startCharI = nextCharI;
}
nextCharI = GetFirstCharIndexFromLine(lineI+1);
if (nextCharI < startCharI) {
nextCharI = sLen;
if ( startCharI == nextCharI ) {
break;
}
}
int lenOfLine = nextCharI - startCharI;
Match match = regex.Match(s, startCharI, lenOfLine);
while ( match.Success ) {
Point point = this.GetPositionFromCharIndex(match.Index);
//Point point2 = this.GetPositionFromCharIndex(match.Index+match.Length);
//g.FillRectangle(brush, point.X, point.Y, point2.X - point.X, lineHeight);
if ( s[match.Index] == '\t' ) {
g.DrawString(">", this.Font, brush, adjX+point.X, adjY+point.Y, new StringFormat());
}
else if ( s[match.Index] == ' ' ) {//全角空白
g.DrawString("□", this.Font, brush, adjX+point.X, adjY+point.Y, new StringFormat());
}
else if ( s[match.Index] == '\r' ) {
g.DrawString(@"\r", this.Font, brush, adjX+point.X, adjY+point.Y, new StringFormat());
}
match = match.NextMatch();
}
/*
// ちらつきと残骸が残る。実用レベルではない
//
// drawstringでtabの描画で調整がやっかいなので、1文字ずつGetPositionFromCharIndexで場所を取得して描画する
Point pointNext = new Point(0,0);
for ( int i=startCharI; i<startCharI+lenOfLine; i++ ) {
Point point;
if ( i == startCharI ) {
point = this.GetPositionFromCharIndex(i);
}
else {
point = pointNext;
}
pointNext = this.GetPositionFromCharIndex(i+1);
if ( pointNext.X < 0 ) {
continue;
}
if ( point.X >= this.Width ) {
break;
}
g.DrawString(new string(s[i],1), this.Font, Brushes.Blue, adjX+point.X, adjY+point.Y, new StringFormat());
}
*/
}
}
public override string Text
{
get {
var getLength = new GETTEXTLENGTHEX();
getLength.flags = GTL_CLOSE; //get buffer size
getLength.codepage = 1200; //Unicode
int textLength = (int)(NativeMethods.SendMessage(this.Handle, EM_GETTEXTLENGTHEX, ref getLength, IntPtr.Zero).ToInt64());
var getText = new GETTEXTEX();
getText.cb = textLength + 2; //add space for null terminator
if ( getText.cb < 2 ) { return ""; } // overflow
getText.flags = GT_DEFAULT;
getText.codepage = 1200; //Unicode
var sb = new StringBuilder(getText.cb);
NativeMethods.SendMessage(this.Handle, EM_GETTEXTEX, ref getText, sb);
return sb.ToString();
}
set { base.Text = value; }
}
public override int TextLength
{
get {
var getLength = new GETTEXTLENGTHEX();
getLength.flags = GTL_DEFAULT; //Returns the number of characters
getLength.codepage = 1200; //Unicode
int textLength = (int)(NativeMethods.SendMessage(this.Handle, EM_GETTEXTLENGTHEX, ref getLength, IntPtr.Zero).ToInt64());
if ( textLength < 0 ) { return 0; } // overflow
return textLength;
}
}
private void SetFixFont()
{
IntPtr lParam = NativeMethods.SendMessage(this.Handle, EM_GETLANGOPTIONS, new IntPtr(0), new IntPtr(0));
lParam = new IntPtr( ((long)lParam) & (~IMF_DUALFONT));
NativeMethods.SendMessage(this.Handle, EM_SETLANGOPTIONS, new IntPtr(0), lParam);
}
private void SetTabStop(int tabSize)
{
int[] tabarray = new int[] { tabSize*4 };
int wparam = tabarray.Length;
IntPtr parray = Marshal.AllocCoTaskMem(Marshal.SizeOf(typeof(int)) * tabarray.Length);
Marshal.Copy(tabarray, 0, parray, tabarray.Length);
NativeMethods.SendMessage(this.Handle, EM_SETTABSTOPS, new IntPtr(wparam), parray);
}
}
class RichTextBoxSample : Form
{
MyRichTextBox txt;
RichTextBoxSample()
{
ClientSize = new Size(600, 250);
Controls.Add(txt = new MyRichTextBox(){
Dock = DockStyle.Fill,
Multiline = true,
WordWrap = false,
AcceptsTab = true,
ScrollBars = RichTextBoxScrollBars.Both,
});
Font baseFont = new Font("ＭＳ ゴシック", 10);
txt.Font = baseFont;
}
[STAThread]
static void Main()
{
Application.Run(new RichTextBoxSample());
}
}