The WM_CTLCOLORBTN message is sent to the parent window of a button when the button is about to be drawn. By responding to this message, the parent window can set a button's text and background colors.
WM_CTLCOLORBTN
hdcButton = (HDC) wParam; // handle of button display context
hwndButton = (HWND) lParam; // handle of button
Parameters
hdcButton
Value of wParam. Identifies the display context for the button.
hwndButton
Value of lParam. Identifies the button.
Return Values
If an application processes this message, it must return the handle of a brush. Windows uses the brush to paint the background of the button.
Default Action
The DefWindowProc function selects the default system colors for the button.
Remarks
The WM_CTLCOLORBTN message is never sent between threads. It is sent only within one thread.
The text color of a check box or radio button applies to the box or button, its check mark, and the text. The focus rectangle for these buttons remains the system default color (typically black). The text color of a group box applies to the text but not to the line that defines the box. The text color of a push button applies only to its focus rectangle; it does not affect the color of the text.
See Also
DefWindowProc, RealizePalette, SelectPalette, WM_CTLCOLORDLG, WM_CTLCOLOREDIT, WM_CTLCOLORLISTBOX, WM_CTLCOLORMSGBOX, WM_CTLCOLORSCROLLBAR, WM_CTLCOLORSTATIC