WM_CTLCOLORMSGBOX Overview  Group

The WM_CTLCOLORMSGBOX message is sent to the owner window of a message box before Windows draws the message box. By responding to this message, the owner window can set the text and background colors of the message box by using the given display device context handle.

WM_CTLCOLORMSGBOX 

hdcMB = (HDC) wParam;   // handle of message box display context 

hwndMB = (HWND) lParam; // handle of message box 

 

Parameters

hdcMB

Value of wParam. Identifies the device context for the message box.

hwndMB

Value of lParam. Identifies the message box.

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 message box.

Default Action

The DefWindowProc function selects the default system colors for the message box.

Remarks

The WM_CTLCOLORMSGBOX message is never sent between threads. It is sent only within one thread.

See Also

DefWindowProc, RealizePalette, SelectPalette, WM_CTLCOLORBTN, WM_CTLCOLORDLG, WM_CTLCOLOREDIT, WM_CTLCOLORLISTBOX, WM_CTLCOLORSCROLLBAR, WM_CTLCOLORSTATIC