| LRESULT DefDlgProc(hwndDlg, uMsg, wParam, lParam) | |||||
| HWND hwndDlg; | /* handle of dialog box | */ | |||
| UINT uMsg; | /* message | */ | |||
| WPARAM wParam; | /* first message parameter | */ | |||
| LPARAM lParam; | /* second message parameter | */ | |||
The DefDlgProc function provides default processing for any Windows messages that a dialog box with a private window class does not process.
hwndDlg
Identifies the dialog box.
uMsg
Specifies the message number.
wParam
Specifies additional message-dependent information.
lParam
Specifies additional message-dependent information.
The return value specifies the result of the message processing and depends on the actual message sent.
The DefDlgProc function is the window procedure for the DIALOG window class. An application that creates new window classes that inherit dialog box functionality should use this function. DefDlgProc is not intended to be called as the default handler for messages within a dialog box procedure, since doing so will result in recursive execution.
An application creates a dialog box by calling one of the following functions:
| Function | Description |
| CreateDialog | Creates a modeless dialog box. |
| CreateDialogIndirect | Creates a modeless dialog box. |
| CreateDialogIndirectParam | Creates a modeless dialog box and passes data to it when it is created. |
| CreateDialogParam | Creates a modeless dialog box and passes data to it when it is created. |
| DialogBox | Creates a modal dialog box. |
| DialogBoxIndirect | Creates a modal dialog box. |
| DialogBoxIndirectParam | Creates a modal dialog box and passes data to it when it is created. |
| DialogBoxParam | Creates a modal dialog box and passes data to it when it is created. |
To create a new window class that inherits dialog functionality, query the default dialog class information and create a clone of this class with your own application attributes:
GetClassInfo(hModule, (LPSTR)DIALOGCLASS, lpWndClass);
lpWndClass.lpszClassName = "mydialogclass";
RegisterClass(lpWndClass);
Or, you can create your own class directly, as long as you reserve the proper number of window extra bytes that dialog windows require:
wndclass.style = 0L;
...
...
wndclass.cbWndExtra = DLGWINDOWEXTRA;
wndclass.lpfnWndProc = DefDlgProc;
wndclass.lpszClassName = "mydialogclass";
RegisterClass(&wndclass);
If your application wants to use window words in windows of this class, they must be located past DLGWINDOWEXTRA, which is a byte count.
DefWindowProc