CreateDialogIndirectParam

The CreateDialogIndirectParam function creates a modeless dialog box from a dialog box template in memory. 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.

HWND CreateDialogIndirectParam(
  HINSTANCE hInstance,        // handle to application instance
  LPCDLGTEMPLATE lpTemplate,  // pointer to dialog box template
  HWND hWndParent,            // handle to owner window
  DLGPROC lpDialogFunc,       // pointer to dialog box procedure
  LPARAM lParamInit           // initialization value
);
 

Parameters

hInstance

Identifies the instance of the module that will create the dialog box.

lpTemplate

Pointer to a global memory object containing a template that CreateDialogIndirectParam uses to create the dialog box. A dialog box template consists of a header that describes the dialog box, followed by one or more additional blocks of data that describe each of the controls in the dialog box. The template can use either the standard format or the extended format.

In a standard template, the header is a DLGTEMPLATE structure followed by additional variable-length arrays. The data for each control consists of a DLGITEMTEMPLATE structure followed by additional variable-length arrays.

In an extended dialog box template, the header uses the DLGTEMPLATEEX format and the control definitions use the DLGITEMTEMPLATEEX format.

After CreateDialogIndirectParam returns, you can free the template, which is only used to get the dialog box started.

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.

lParamInit

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 window handle to the dialog box.

If the function fails, the return value is NULL. To get extended error information, call GetLastError.

Remarks

The CreateDialogIndirectParam function uses the CreateWindowEx function to create the dialog box. CreateDialogIndirectParam then sends a WM_INITDIALOG message to the dialog box procedure. If the template specifies the DS_SETFONT style, the function also sends a WM_SETFONT message to the dialog box procedure. The function displays the dialog box if the template specifies the WS_VISIBLE style. Finally, CreateDialogIndirectParam returns the window handle to the dialog box.

After CreateDialogIndirectParam returns, you can use the ShowWindow function to display the dialog box (if it is not already visible). To destroy the dialog box, use the DestroyWindow function.

In a standard dialog box template, the DLGTEMPLATE structure and each of the DLGITEMTEMPLATE structures must be aligned on DWORD boundaries. The creation data array that follows a DLGITEMTEMPLATE structure must also be aligned on a DWORD boundary. All of the other variable-length arrays in the template must must be aligned on WORD boundaries.

In an extended dialog box template, the DLGTEMPLATEEX header and each of the DLGITEMTEMPLATEEX control definitions must be aligned on DWORD boundaries. The creation data array, if any, that follows a DLGITEMTEMPLATEEX structure must also be aligned on a DWORD boundary. All of the other variable-length arrays in the template must be aligned on WORD boundaries.

All character strings in the dialog box template, such as titles for the dialog box and buttons, must be Unicode strings. To create code that works on both Windows and Windows NT, use the MultiByteToWideChar function to generate these Unicode strings.

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: Dialog boxes outside the visible area of the screen are not automatically repositioned.

If the user presses ALT+H while the dialog box has the input focus, the system posts a WM_HELP message to the dialog procedure. An application should respond to this message by displaying context-sensitive help for the dialog box.

The following styles are not supported for the style member of the DLGTEMPLATE structure:

• DS_SETFONT: You cannot set the font inside dialog boxes.
• DS_3DLOOK
• DS_RECURSE: Not required. Any child dialog box is automatically considered to be a recursive dialog box.
• DS_CONTROL: Not required.
• WS_EX_CONTROLPARENT: All dialog boxes are automatically assumed to be control parents.

To get default positioning, use the DS_CENTER style.

If the WS_CHILD style is not specified, the WS_POPUP style is assumed.

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, CreateDialog, CreateDialogIndirect, CreateDialogParam, CreateWindowEx, DestroyWindow, DialogProc, DLGITEMTEMPLATE, DLGITEMTEMPLATEEX, DLGTEMPLATE, DLGTEMPLATEEX, MultiByteToWideChar, ShowWindow, WM_INITDIALOG, WM_SETFONT