Public Class Main
    Public Shared Class Main(args() as String)
        Dim i as Integer = 0
        Do until i > args.length
            .... 'auslesen der Parameter
        Loop
    End Sub
End Class

Dim i As Integer = 0
While i < args.Length
    If args(i) = "-i" Then
        If args(i).Length = 2 Then
            LogDialog.WriteLine(args(i), Log.Icon.Error)
            LogDialog.WriteLine("need complete path of inputfile", _
              Log.Icon.Unknown)
        End If
    ElseIf args(i) = "-o" Then
        If args(i).Length = 2 Then
            LogDialog.WriteLine(args(i), Log.Icon.Error)
            LogDialog.WriteLine("need complete outputpath", Log.Icon.Unknown)
        End If
     End If
     i += 1
End While