How to prevent graphics remove from panel onPaint?

I have a Canvas class who is Panel-inherited class that overrides the onPaint method.

My program looks like this:

enter image description here

It works good and all, but when I minimize \ resize the Canvas,

the "hidden" part of the canvas is deleting. I've noticed that I have to override the onPaint method.

But I don't know what to do to "keep" the draw. any suggestion?

Solution

You are describing something that happens when you use CreateGraphics. Don't use CreateGraphics, but use the graphic object from the PaintEventArgs parameter, specifically e.Graphics.