TextBox with vertical scrollbar on the left side

Question

I\'m developing a Windows Forms application in C#, which has a multiline TextBox control on a form.

Due to specific (irrelevant) reasons, this TextBox needs a vertic

Answer 1

I took some of the example code from Rachel Gallen's link and made this version of the TextBox:

public class TextBoxWithScrollLeft : TextBox {
  private const int GWL_EXSTYLE = -20;
  private const int WS_EX_LEFTSCROLLBAR = 16384;

  [DllImport("user32", CharSet = CharSet.Auto)]
  public extern static int GetWindowLong(IntPtr hWnd, int nIndex);

  [DllImport("user32")]
  public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

  protected override void OnHandleCreated(EventArgs e) {
    base.OnHandleCreated(e);
    int style = GetWindowLong(Handle, GWL_EXSTYLE);
    style = style | WS_EX_LEFTSCROLLBAR;
    SetWindowLong(Handle, GWL_EXSTYLE, style);
  }
}

I've never done it before, but the results seem to have worked: