It doesn't draw above com-component ...

Question

I have a graphical com-component from our vendor. I placed it in main form and want to draw above it. But MainForm_paint doesn't draw above that component. Is there any way to paint above that component ?

C#, WinForms, 2.0

code:

    void MainForm_Paint(object sender, PaintEventArgs e)
    {
            using (SolidBrush b2 = new SolidBrush(Color.Red))
            {
                e.Graphics.FillRectangle(b2, this.ClientRectangle);
            }

            Pen pen = new Pen(Color.Black, 2.0f);
            e.Graphics.DrawLine(pen, 0, 0, 100, 100);
            pen.Dispose();
    }

It didn't fill anything and it didn't draw a line. ComComponent.DockStyle = DockStyle.Fill

Answer 1

you cannot draw above the component. ActiveX has its own Paint message. if Paint event is visible in your container(winform) you may override it.

Answer 2

If you can set the control's background to transparent, do that. Otherwise, it might be possible to subclass the control's window and ignore WM_ERASEBKGND (or whatever it's called).

Or if you know exactly where you want to paint, you can place a non-rectangular window above the ActiveX control.

Edit: Added last suggestion