Question

do you know how to force a Richtextbox to redraw ONLY it’s foreground (not background).

Should i send a message or something like that ?

Thanks !

Answer 1

You can override the OnPaintBackground method.

protected override void OnPaintBackground(PaintEventArgs pevent)
{
    if (_I_need_to_paint_background) {
        base.OnPaintBackground(pevent)
    }
}

Of cause this means that you have to derive your own RichTextBox form the original

public class MyRichTextBox : RichTextBox
{
    ...

    protected override void OnPaintBackground(PaintEventArgs pevent)
    {
        // Your background painting logic goes here
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        // Your foreground painting logic goes here
    }
}

With the Invalidate method of controls you can tell controls that they should redraw themselves. The Refresh method invalidates a control and tells it to redraw itself immediately (using OnPaintBackground and OnPaint).