DialogBoxParam

The DialogBoxParam function 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.

int DialogBoxParam(
  HINSTANCE hInstance,  // handle to application instance
  LPCTSTR lpTemplateName,  // identifies dialog box template
  HWND hWndParent,      // handle to owner window
  DLGPROC lpDialogFunc, // pointer to dialog box procedure
  LPARAM dwInitParam    // initialization value
);
 

Parameters

hInstance

Identifies an instance of the module whose executable file contains the dialog box template.

lpTemplateName

Identifies 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.

hWndParent

Identifies the window that owns the dialog box.

lpDialogFunc

Pointer to the dialog box procedure. For more information about the dialog box procedure, see DialogProc.

dwInitParam

Specifies the value to pass to the dialog box in the lParam parameter of the WM_INITDIALOG message.

Return Values

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, 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 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.

Windows 95 and later: The system can support a maximum of 255 controls per dialog box template. To place more than 255 controls in a dialog box, create the controls in the WM_INITDIALOG message handler rather than placing them in the template.

Windows CE: Not all styles are supported in the DLGTEMPLATE structure in the dialog template referred to by the lpTemplateName parameter.

QuickInfo

  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.

See Also

Dialog Boxes Overview, Dialog Box Functions, CreateWindowEx, DialogBox, DialogBoxIndirect, DialogBoxIndirectParam, DialogProc, EndDialog, MAKEINTRESOURCE, WM_INITDIALOG, WM_SETFONT