Viewing Dialog Template Resources at Runtime

In many resource applications, it is necessary to display a preview of the application's dialog template resource(s). This article presents a class (CPreviewStatic) that can be used to preview dialog template resources at runtime with a single line of code!

Using the CPreviewStatic class

In order to use this class, simple place a static text control on the dialog where you want to display the dialog template resource at runtime. Then, subclass the control with a call to SubclassDlgItem.

	m_stcPreview.SubclassDlgItem(IDC_STATIC_PREVIEW, this);

Once you have subclassed the text control, modify the CPreviewStatic::PreSubclassWindow function to load the desired dialog template resource. To do this, simply modify the LoadResource function call by specifying the correct resource id.

That's it! With only two steps you can view any of your application's dialog templates at runtime. For the more curious among you, the actual code to implement this functionality is presented below. If you have any questions or need any help, please feel free to contact me: Mihai Filimon. Enjoy!

Implementation of the CPreviewStatic class

The (CPreviewStatic::Preview) member function takes, as its only argument, a handle to a memory block where a dialog template resource is stored. A dialog template resource can be loaded into memory using the LoadResource Win32 SDK function. You can see how this is done in the demo project (CPreviewStatic::PreSubclassWindow). CPreviewStatic::Preview then returns a pointer to a bitmap that is a preview of the desired dialog template resource.

// Function name : CPreviewStatic::Preview 
// Description   : Take a handle of memory dialog resource and return the bitmap with preview 
// Return type   : CBitmap* 
// Argument      : HGLOBAL hGlobal 
CBitmap* CPreviewStatic::Preview(HGLOBAL hGlobal) 
{ 
 CBitmap* pBitmap = NULL, bitmapNonClient; 
 if (LPCDLGTEMPLATE pTemplate = (LPCDLGTEMPLATE)::LockResource(hGlobal)) 
 { 
  CWnd* pParent = AfxGetMainWnd(); 
  if (HWND hwnd = CreateDialogIndirectParam(AfxGetInstanceHandle(), pTemplate, 
   pParent->m_hWnd, NULL, NULL)) 
  { 
   CWnd* pWnd = CWnd::FromHandle(hwnd); 
   CRect rectWindow; pWnd->GetWindowRect(rectWindow); 
   CRect rectClient; pWnd->GetClientRect(rectClient); 
   CPoint p(0,0); 
   pWnd->ClientToScreen(&p); 
   rectClient.OffsetRect(p.x - rectWindow.left, p.y - rectWindow.top); 
   CDC* pDC = pWnd->GetDC(); 
   CDC dcMemSourceNonClient, dcMemDestination; 
   if (dcMemSourceNonClient.CreateCompatibleDC(pDC)) 
    if (dcMemDestination.CreateCompatibleDC(pDC)) 
     if (pBitmap = new CBitmap()) 
      if (pBitmap->CreateCompatibleBitmap(pDC, rectWindow.Width(), rectWindow.Height())) 
       if (bitmapNonClient.CreateCompatibleBitmap(pDC, rectWindow.Width(), rectWindow.Height())) 
       { 
        CBitmap* pOldNonClientBitmap = 
        dcMemSourceNonClient.SelectObject(&bitmapNonClient); 
        CBrush brush(RGB(192, 192, 192)); 
        CBrush* pOldBrush = dcMemSourceNonClient.SelectObject(&brush); 
        dcMemSourceNonClient.PatBlt(0,0,rectWindow.Width(), rectWindow.Height(), 
         PATCOPY); 
        dcMemSourceNonClient.SelectObject(pOldBrush); 
        dcMemDestination.SelectObject(pBitmap); 
        pWnd->Print(&dcMemSourceNonClient, PRF_NONCLIENT ); 
        dcMemDestination.BitBlt(0,0,rectWindow.Width(), rectWindow.Height(), 
         &dcMemSourceNonClient, 0,0, SRCCOPY); 
        pWnd->Print(&dcMemDestination, PRF_CHILDREN | PRF_CLIENT); 
        dcMemSourceNonClient.SelectObject(pOldNonClientBitmap); 
        bitmapNonClient.DeleteObject(); 
       } 
   pWnd->DestroyWindow(); 
  } 
 } 
 return pBitmap; 
}