Private Declare Function SHGetFileInfo Lib "shell32.dll" Alias "SHGetFileInfoA" _
  (ByVal pszPath As String, ByVal dwFileAttributes As Integer, ByRef psfi As _
  SHFILEINFO, ByVal cbFileInfo As Integer, ByVal uFlags As Integer) As IntPtr
 
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Structure SHFILEINFO
	Public hIcon As Integer
	Public iIcon As Integer
	Public dwAttributes As Integer
	Public szDisplayName As String
	Public szTypeName As String
End Structure
 
'wenn ich das jetzt so aufrufe:
 
Public Function GetTypeName as String
dim psfi as new shfileinfo
shgetfileinfo("C:\Datei.txt", 0, psfi, len(psfi), &H101)
return psfi.szTypename
end function
 
'dann ist der string jeweils leer. weshalb?