DOC:CDocTemplate::CreateNewFrame() Won't Make New CDocument

ID: Q121321

The information in this article applies to:

The Microsoft Foundation Classes (MFC), included with:
- Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51
- Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0

SUMMARY

The Help File documentation for CDocTemplate::CreateNewFrame() says:


   If the pDoc parameter is NULL, a new document will be created
   if the appropriate runtime class is available; otherwise the
   new view will be associated with the ...

This is not correct. Calling CreateNewFrame() with a NULL pDoc parameter actually results in an assertion failure on the pDoc pointer and a TRACE() statement in your output or debug window stating the following:

ASSERT_VALID fails with NULL pointer.

The reason for this is that CreateNewFrame() is not the appropriate function to call when you don't have a pre-constructed CDocument-derived object. The function to call is CMultiDocTemplate's or CSingleDocTemplate's OpenDocumentFile(). The OpenDocumentFile() function creates a new CDocument object by using CreateNewDocument().

MORE INFORMATION

CMultiDocTemplate:: and CSingleDocTemplate::OpenDocumentFile() both create a new document if the pointer argument passed to them is NULL. To get a pointer to the appropriate document template that you can use when calling OpenDocumentFile(), please see the following article in the Microsoft Knowledge Base:

Q106455 Acquiring a List of All CDocument Objects

This article contains sample code you can use to traverse the list of available document templates.

This problem was fixed in Microsoft Visual C++, 32-bit Edition, version 4.0.

Additional query words: pDoc ASSERT_VALID OpenDocumentFile 1.00 1.50 2.00 2.10 2.50 2.51 3.00 4.00

Keywords : kbdocfix
Version : 1.00 1.50 1.51 | 1.00 2.00
Platform : NT WINDOWS
Issue type :