If string parameter is going to be changed then it's better to declare
it as StringBuilder. Params declared as String sometimes work, sometimes
not. Also with StringBuilder class you don't have to worry about
trailing spaces or zero characters.
In addition, I can't imagine why do you need to call ANSI version of the
function. Apply the Auto modifier (Charset:=CharSet.Auto in your case)
and let runtime choose.
So...
~
Friend Declare Auto Function GetLongPathName Lib "kernel32.dll" ( _
<MarshalAs(UnmanagedType.LPTStr), [In]()> ByVal lpszShortPath As
String, _
<MarshalAs(UnmanagedType.LPTStr)> ByVal lpszLongPath As
StringBuilder, _
ByVal cchBuffer As Integer _
) As Integer
REM If you still want to use ANSI version then that's it:
Friend Declare Ansi Function GetLongPathNameA Lib "kernel32.dll" ( _
<MarshalAs(UnmanagedType.LPStr), [In]()> ByVal lpszShortPath As
String, _
<MarshalAs(UnmanagedType.LPStr)> ByVal lpszLongPath As
StringBuilder, _
ByVal cchBuffer As Integer _
) As Integer
Private Function LongPathName(ByVal shortPathName As String) As
String
Dim RV As Integer
Dim LongPath As StringBuilder = Nothing
'Determine the size of the buffer needed.
RV = GetLongPathNameA(shortPathName, Nothing, 0)
If RV = 0 Then Return String.Empty
'Allocate storage for the buffer and call again.
LongPath = New StringBuilder(RV)
RV = GetLongPathNameA(shortPathName, LongPath,
LongPath.Capacity)
If RV = 0 Then Return String.Empty
Return LongPath.ToString
End Function
~
Just a note. Some API functions let you call them with no buffer;
however, this one does not.
ie RV = GetShortPathNameW(longPathName, Nothing, 0)
?
The example above works just fine for me and you see it uses Nothing for
buffer.
Roman
