onpaintbackground

Question

i did override onpaintbackground of Form() how can i update tthis? because when form startup it shown withoutbackground but it give startup bg position for yourself and dont chnange i wanna delete background control for forms (c#.net)

Richard Blythe · Answer

I couldn't understand everything you said but I believe that you are wanting to make changes to background and have it update the display. This same situation used to cause me to "pull my hair out"! :-> It seemes as if the application completely ignored my instructions. The magic word to this whole thing is "Invalidate". This is the programmers way to tell the form it needs to update itself. Or even better for performance: a specified area to update itself. One thing that isn't very clear to the naked eye is that when the Form repaints itself, it is using a paint technique call "Clipping", which means the Form normally makes the decision on what area to repaint. Even though the whole OnPaintBackground appears to run, only the areas inside the clipping rectangle are repainted. The this.Invalidate(); method tells the form to repaint its entire surface. As a note for performance, its always better to specify the exact area to repaint when working with smaller graphics. Cheers! Richard

onpaintbackground

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