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
);
The return value specifies the result of the message processing and depends on the message sent.
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 NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Requires version 1.0 or later.
Header: Declared in winuser.h.
Import Library: Use user32.lib.
Unicode: Implemented as Unicode and ANSI versions on Windows NT.
Dialog Boxes Overview, Dialog Box Functions, DefWindowProc, GetClassInfo, RegisterClass, WNDCLASS