Shell API programming

I want to fill a listview with the Windows desktop's full filenames.
But when I've used the SHGetSpecialFolderPath, I couldn't reach the full filename, because the DisplayName property gives back e.g. "exename" instead of "exename.exe" (no extension), so I couldn't access the full filenames.

(I've found function SHGetFileInfo, SSF_SHOWEXTENSIONS is readable, but I couldn't found a function to set it).