DialogBoxParamA function (winuser.h)
Creates a modal dialog box from a dialog box template resource. Before displaying the dialog box, the function passes an application-defined value to the dialog box procedure as the lParam parameter of the WM_INITDIALOG message. An application can use this value to initialize dialog box controls.
Syntax
INT_PTR DialogBoxParamA(
[in, optional] HINSTANCE hInstance,
[in] LPCSTR lpTemplateName,
[in, optional] HWND hWndParent,
[in, optional] DLGPROC lpDialogFunc,
[in] LPARAM dwInitParam
);
Parameters
[in, optional] hInstance
Type: HINSTANCE
A handle to the module which contains the dialog box template. If this parameter is NULL, then the current executable is used.
[in] lpTemplateName
Type: LPCTSTR
The dialog box template. This parameter is either the pointer to a null-terminated character string that specifies the name of the dialog box template or an integer value that specifies the resource identifier of the dialog box template. If the parameter specifies a resource identifier, its high-order word must be zero and its low-order word must contain the identifier. You can use the MAKEINTRESOURCE macro to create this value.
[in, optional] hWndParent
Type: HWND
A handle to the window that owns the dialog box.
[in, optional] lpDialogFunc
Type: DLGPROC
A pointer to the dialog box procedure. For more information about the dialog box procedure, see DialogProc.
[in] dwInitParam
Type: LPARAM
The value to pass to the dialog box in the lParam parameter of the WM_INITDIALOG message.
Return value
Type: INT_PTR
If the function succeeds, the return value is the value of the nResult parameter specified in the call to the EndDialog function used to terminate the dialog box.
If the function fails because the hWndParent parameter is invalid, the return value is zero. The function returns zero in this case for compatibility with previous versions of Windows. If the function fails for any other reason, the return value is –1. To get extended error information, call GetLastError.
Remarks
The DialogBoxParam function uses the CreateWindowEx function to create the dialog box. DialogBoxParam then sends a WM_INITDIALOG message (and a WM_SETFONT message if the template specifies the DS_SETFONT or DS_SHELLFONT style) to the dialog box procedure. The function displays the dialog box (regardless of whether the template specifies the WS_VISIBLE style), disables the owner window, and starts its own message loop to retrieve and dispatch messages for the dialog box.
When the dialog box procedure calls the EndDialog function, DialogBoxParam destroys the dialog box, ends the message loop, enables the owner window (if previously enabled), and returns the nResult parameter specified by the dialog box procedure when it called EndDialog.
Note
The winuser.h header defines DialogBoxParam as an alias that automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that is not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | winuser.h (include Windows.h) |
| Library | User32.lib |
| DLL | User32.dll |
| API set | ext-ms-win-ntuser-dialogbox-l1-1-1 (introduced in Windows 8.1) |
See also
Conceptual
Reference