Disable Painting of the VScrollbar in a System.Windows.Forms.RichTextBox

Question

I have a custom control inherited from RichTextBox. This control has the ability to \"disable\" rich text editing. I achive this by just setting the Rtf property to the text

Answer 1

SuspendLayout() isn't going to have an effect, there are no child controls inside an RTB that need to be arranged. RTB is missing the Begin/EndUpdate() methods that most controls have, although it supports it. It suspends painting, although I'm not so sure it suspends updates to the scrollbar. Add them as follows:

public void BeginUpdate() {
  SendMessage(this.Handle, WM_SETREDRAW, (IntPtr)0, IntPtr.Zero);
}
public void EndUpdate() {
  SendMessage(this.Handle, WM_SETREDRAW, (IntPtr)1, IntPtr.Zero); 
}

// P/invoke declarations
private const int WM_SETREDRAW = 0xb;
[System.Runtime.InteropServices.DllImport("user32.dll")]
private extern static IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wp, IntPtr lp); 

The better way to prevent the user from editing text is to set the ReadOnly property to True. Removing the scrollbar entirely is possible too by overriding CreateParams.