Streamwriter error handling

I am using streamwriter to write to a file. It faiils to create a file but doesn't generate an exception.

How do I find an error?

try
  Dim objStreamWriter As StreamWriter
            objStreamWriter = File.CreateText(UniquefileName)
            objStreamWriter.Write(strOutput)
            'Close the stream
            objStreamWriter.Close()


        Catch ex As Exception
            SendError(ex.Message)
        End Try