The DefDlgProc function carries out default message processing for a window procedure belonging to an application-defined dialog box class.
LRESULT DefDlgProc(
| HWND hDlg, | // handle to dialog box |
| UINT Msg, | // message |
| WPARAM wParam, | // first message parameter |
| LPARAM lParam | // second message parameter |
| ); |
Parameters
hDlg
Identifies the dialog box.
Msg
Specifies the message number.
wParam
Specifies additional message-specific information.
lParam
Specifies additional message-specific information.
Return Values
The return value specifies the result of the message processing and depends on the message sent.
Remarks
The DefDlgProc function is the window procedure for the predefined class of dialog box. This procedure provides internal processing for the dialog box by forwarding messages to the dialog box procedure and carrying out default processing for any messages that the dialog box procedure returns as FALSE. Applications that create custom window procedures for their custom dialog boxes often use DefDlgProc instead of the DefWindowProc function to carry out default message processing.
Applications create custom dialog box classes by filling a WNDCLASS structure with appropriate information and registering the class with the RegisterClass function. Some applications fill the structure by using the GetClassInfo function, specifying the name of the predefined dialog box. In such cases, the applications modify at least the lpszClassName member before registering. In all cases, the cbWndExtra member of WNDCLASS for a custom dialog box class must be set to at least DLGWINDOWEXTRA.
The DefDlgProc function must not be called by a dialog box procedure; doing so results in recursive execution.
See Also