Anyone know why this doesn't work

[Jeremy Martin]

Does anyone know why this doesn't work?

Public Class Class1
Declare Function GetUserName Lib "advapi32.dll" Alias "GetUserNameA" (ByVal lpBuffer As String, ByVal NSize As Long) As Long

Public Function SysGetUserName() As String
Dim UserName As String
Dim BufSize As Long
Dim RetCode As Long
Dim NullCharPos As Long

UserName = Space(80)
BufSize = Len(UserName)

RetCode = GetUserName(UserName, BufSize)

NullCharPos = InStr(UserName, Chr(0))

If NullCharPos > 0 Then
UserName = Left(UserName, NullCharPos - 1)
Else
UserName = ""
End If

MsgBox(UserName)
End Function
End Class

[hellswraith]

My guess is that you are trying to access a API call using mismatched variable types.

Change your longs to integers, that might work. The integers in .Net are now what the API calls longs.

[Pirate]

try using this structure :

try 
 ' perform operation that will generates an error 

catch x as system.exception 
messagebox.show(x.message)

end try

hope this catches your bug

[Jeremy Martin]

The refernce is Object reference not set to an instance of an object.

Thanks
Jeremy