The WM_CTLCOLORDLG message is sent to a dialog box before Windows draws the dialog box. By responding to this message, the dialog box can set its text and background colors by using the given display device context handle.
WM_CTLCOLORDLG
hdcDlg = (HDC) wParam; // handle of dialog box display context
hwndDlg = (HWND) lParam; // handle of dialog box
Parameters
hdcDlg
Value of wParam. Identifies the device context for the dialog box.
hwndDlg
Value of lParam. Identifies the dialog 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 dialog box.
Default Action
The DefWindowProc function selects the default system colors for the dialog box.
Remarks
The WM_CTLCOLORDLG message is never sent between threads. It is sent only within one thread.
Note that the WM_CTLCOLORDLG message is sent to the dialog box itself; all of the other WM_CTLCOLOR* messages are sent to the owner of the control.
See Also
DefWindowProc, RealizePalette, SelectPalette, WM_CTLCOLORBTN, WM_CTLCOLOREDIT, WM_CTLCOLORLISTBOX, WM_CTLCOLORMSGBOX, WM_CTLCOLORSCROLLBAR, WM_CTLCOLORSTATIC