[C#]
           //create a RtfToTextTransform
            using (RtfToTextTransformc = new RtfToTextTransform())
            {
                 c.Load("SimpleTest.rtf"); //load the rtf file
                 c.Transform("SimpleTest.txt"));//transform to txt file
            }

[VB.NET]
           'create a RtfToTextTransform
            Dim c As RtfToTextTransform= New RtfToTextTransform();
            c.Load("SimpleTest.rtf") 'load the rtf file
            c.Transform("SimpleTest.txt")) 'transform to txt file
            c.Dispose()