The DefDlgProc function calls the default dialog box window procedure to provide default processing for any window messages that a dialog box with a private window class does not process.
Syntax
LRESULT DefDlgProc(
HWND hDlg,
UINT Msg,
WPARAM wParam,
LPARAM lParam
);
Parameters
- hDlg
-
[in] Handle to the dialog box.
- Msg
-
[in] Specifies the message.
- wParam
-
[in] Specifies additional message-specific information.
- lParam
-
[in] Specifies additional message-specific information.
Return Value
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.
Windows 95/98/Me: DefDlgProcW is supported by the Microsoft Layer for Unicode. To use this, you must add certain files to your application, as outlined in Microsoft Layer for Unicode on Windows 95/98/Me Systems.
Function Information
| Minimum DLL Version | user32.dll |
|---|
| Header | Declared in Winuser.h, include Windows.h |
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| Import library | User32.lib |
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| Minimum operating systems |
Windows 95, Windows NT 3.1 |
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| Unicode | Implemented as
Unicode version. |
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See Also