c# - How do you prevent a RichTextBox from refreshing its display?

Question

I have a RichTextBox where I need to update the Text property frequently, but when I do so the RichTextBox "blinks" annoyingly as it refreshes all throughout a method call.

I was hoping to find an easy way to temporarily suppress the screen refresh until my method is done, but the only thing I've found on the web is to override the WndProc method. I've employed this approach, but with some difficulty and side effects, and it makes debugging harder, too. It just seems like there's got to be a better way of doing this. Can someone point me to a better solution?

Answer 1

Here is complete and working example:

    private const int WM_USER = 0x0400;
    private const int EM_SETEVENTMASK = (WM_USER + 69);
    private const int WM_SETREDRAW = 0x0b;
    private IntPtr OldEventMask;       

    [DllImport("user32.dll", CharSet=CharSet.Auto)]
    private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

    public void BeginUpdate()
    {
        SendMessage(this.Handle, WM_SETREDRAW, IntPtr.Zero, IntPtr.Zero);
        OldEventMask = (IntPtr)SendMessage(this.Handle, EM_SETEVENTMASK, IntPtr.Zero, IntPtr.Zero);
    }       

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