Refresh a region in window before drawing text

I'm drawing text on window at WM_PAINT message, is there any way i can refresh that window region before drawing a new line of text so the old tex开发者_开发百科t at the same location would get erased?

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You need to call InvalidateRect for the window with the bErase parameter set to TRUE so that it will erase itself before the WM_PAINT is generated.

This is often required when the window is a static text control, as those don't erase themselves automatically when you change their value.

Make sure your window is handling WM_ERASEBKGND properly and the window class doesn't have a NULL background brush, as this is the mechanism used by InvalidateRect to do the erasing.

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You could just FillRect over the old text first...

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HDC hdc = GetDC(NULL); //get windows handle whaterver if urs
HRGN hrgn;

 //get that specific region and repaint it by following line

hrgn = CreateRectRgn(10, 10, 100, 100);
SelectClipRgn(hDC, hrgn);
PaintDesktop(hDC);