NetworkUserName - The user name used to establish a network connection

Private Declare Function WNetGetUser Lib "mpr.dll" Alias "WNetGetUserA" (ByVal _
    lpszLocalName As String, ByVal lpszUserName As String, _
    lpcchBuffer As Long) As Long

' return the current default user name or
' the user name used to establish a connection

Function NetworkUserName() As String
    Dim buffer As String
    buffer = Space$(256)
    ' if the WNetGetUser API returns 0, then
    ' the user name is in buffer
    If WNetGetUser(vbNullString, buffer, Len(buffer)) = 0 Then
        NetworkUserName = Left$(buffer, InStr(buffer, vbNullChar) - 1)
    End If
End Function