How to use a dialog template to create an MFC dialog that contains an ActiveX control (231591)

SUMMARY

It is possible to display a dialog from either a DIALOG resource or from a dialog template in memory. In the latter case, the dialog template is either constructed or loaded into memory and the dialog is created indirectly.

Dialogs that contain ActiveX controls are more difficult to create indirectly because they require additional information such as license keys and the initial states of properties. MFC requires that this additional information be provided as a DLGINIT resource. The Visual C++ resource editor creates this DLGINIT resource in the resource (.rc) file for each dialog containing an ActiveX control.

Both CDialog::CreateIndirect() and CDialog::InitModalIndirect() support using DLGINIT resources with dialog templates in memory. However, the DLGINIT parameter is not documented and by default is set to NULL. The complete prototypes for these functions are:

BOOL CDialog::CreateIndirect(LPCDLGTEMPLATE lpDialogTemplate, CWnd* pParentWnd, void* lpDialogInit, HINSTANCE hInst);

BOOL CDialog::InitModalIndirect(LPCDLGTEMPLATE lpDialogTemplate, CWnd* pParentWnd = NULL,void* lpDialogInit = NULL);

Note Only the versions of these functions which take a LPCDLGTEMPLATE as the first parameter support passing a DLGINIT resource. The versions which take a HGLOBAL parameter do not support DLGINIT resources.

MORE INFORMATION

The following source shows how to load a DIALOG resource from memory and display it indirectly using a dialog template in memory. This function also uses the DLGINIT resource and will work with DIALOG resources that contain ActiveX controls.

void CMainFrame::OnMyModalDialogIndirect() 
{
	//Load DLGTEMPLATE
	DLGTEMPLATE* pTemplate;
 
	HINSTANCE hInst= AfxFindResourceHandle(
                            MAKEINTRESOURCE(IDD_INDIRECT),RT_DIALOG);
	
	if (hInst == NULL)
	{ 
		TRACE("Cound not find resource in resource chain");
		ASSERT(FALSE);
		return;
	}
 
	HRSRC hRsrc = ::FindResource(hInst, MAKEINTRESOURCE(IDD_INDIRECT),
		RT_DIALOG);
	ASSERT(hRsrc != NULL);

	HGLOBAL hTemplate = ::LoadResource(hInst, hRsrc);
	ASSERT(hTemplate != NULL);
 
	pTemplate = (DLGTEMPLATE*)::LockResource(hTemplate);

	//Load coresponding DLGINIT resource
	void* lpDlgInit = NULL;
	HGLOBAL hDlgInit = NULL;

	HRSRC hsDlgInit = ::FindResource(hInst, MAKEINTRESOURCE(IDD_INDIRECT),
                             RT_DLGINIT);
	if (hsDlgInit != NULL)
	{
		// load it
		hDlgInit = ::LoadResource(hInst, hsDlgInit);
		ASSERT(hDlgInit != NULL);

		// lock it
		lpDlgInit = ::LockResource(hDlgInit);
		ASSERT(lpDlgInit != NULL);
	}

	//ToDo: Modify DLGTEMPLATE in memory if desired

	CDialog dlg;
	dlg.InitModalIndirect(pTemplate, NULL, lpDlgInit);  
	dlg.DoModal();    
 
	::UnlockResource(hTemplate);
	::FreeResource(hTemplate);
	if (hDlgInit) 
	{
		::UnlockResource(hDlgInit);   
		::FreeResource(hDlgInit);
	}	
}