تنظیم رنگ پس زمینه ی EDIT CONTROL

EM_SETBKGNDCOLOR

The EM_SETBKGNDCOLOR message sets the background color for a rich edit control.

wParam

Specifies whether to use the system color. If this parameter is a nonzero value, the background is set to the window background system color. Otherwise, the 

.background is set to the specified color

lParam

A COLORREF structure specifying the color if wParam 

.is zero. To generate a COLORREF, use the RGB macro