Control repainting problem

Question

Hello everyone. I just got my hands dirty with C#, and now i am trying to write an application involving GDI+ graphics. Here is the problem that i can't figure out. Maybe someone can help: Details: I use a windows Form as my main drawing space for a problem involving graphs. When you click on the form, the code draws a circle ( wich is a graph node) at the mouse pointer location. All of theese are happening in a button's Click event. The problem is that whenever i minimize the app and then restore it, all of the drawings are gone. How can i save my graphics in such a way that whenever i restore the app from the tray bar, the graphics is still there? PS: I think it's something about the control's Paint Event.

buju banton · Answer

Hi everyone! Still me here. I have found one approach to this problem on this site(which actually works too). That is by first creating a Bitmap object of the size you want and then creating a Graphics object with the FromBitmap() method. Then, whatever drawing takes place it is in the bitmap you just created. Finally, all you need to do is just set the form's or control's BackgroundImage to that Bitmap on the override OnPaint method, thus, everything will still be there when you resize, minimize, etc., the form. Of course, this problem would be gone if you only needed to draw something on the Paint method because, then, you would just have to use the Graphics member of the System.PaintEventArgs object "e" of the paint method. However things get a little dirty when you draw on a button click, on a MouseMove event, etc. So, any new ideas out there? At least thanks for viewing this post :)