C++ Q&A: Windows 2000 File Dialog Revisited; Autocompletion and the ACTest Demo App

摘要

In my April 2000 C++ Q&A column, I answered a question from a reader who asked how to get the Windows~® 2000-style File | Open dialog (the one with the Places bar) in his MFC app. I said essentially, you can't do it. I should have heeded one of my own favorite sayings,"In programming you can always do anything." To restate the problem, Windows 2000 has a new Open dialog (see Figure 1) with a Places bar on the left side. To invoke the dialog, you must call∷GetOpenFileName, passing it an OPENFILENAME struct. MFC wraps this in the class CFileDialog. The problem is that the most recent OPENFILENAME struct (version 5.0 and later, which means Windows 2000) has additional members that increase its size. Before you (or MFC) call∷GetOpenFileName, you must initialize the first member of OPENFILENAME—lStruct-Size—to sizeof(OPENFILENAME). If you compile for Windows 2000 (_WIN32_WINNT >= 0x0500), you'll get the new size; if you compile for earlier versions of Windows, you'll get the old size.