windows.forms.panel calling onPaint twice

I have a panel with multiple panels inside of it. I have overridden OnPaint in the master panel to the following:

    protected override void OnPaint(PaintEventArgs e)
    {
        Graphics graph = e.Graphics;
        graph.Clear(Color.Black);
        InvokePaintBackground(this, e);

        graph.ScaleTransform(scale, scale);

        foreach (childPanel child in childPanels)
        {
            child.onPaint(this, e);
        }

        graph.ResetTransform();
    }

The problem I have is that the onPaint function of the first control (control in spot 0) is being called twice so I am getting two versions of the child panel, one with scaling, and one without. The second onPaint seems to be called by the child control its开发者_高级运维elf.

How do I keep it from doing this?

That's because all Control objects do their own painting and the method is called automatically by Windows. The solution is to not rely on this sort of functionality at all - get rid of the panels, or set Visible to false.

Why on earth are you calling OnPaint on the child control? Windows will manage the paint calls on its own. You should never call them directly, especially with the graphics context you received from a separate paint call!

If you need to request a child control to be painted, use the Invalidate method instead. It marks a region (or entire control) as invalid so that Windows will paint it. The upside to that is that Windows is smart enough to know that if you invalidate it multiple times in the same paint cycle, it won't re-draw multiple times.

It is the inherent behavior. You can simply use a private bool secondCall; sort of a variable and do the scaling only on the second call.