Dim myStreamWriter as StreamWriter
 
If saveFileDialog1.ShowDialog() = DialogResult.OK Then 
myStream = saveFileDialog1.OpenFile
If Not (myStream Is Nothing) Then 
  myStreamWriter = NEw StreamWriter(mystream, false)
  mystreamWriter.writeline(Textbox1.text)
myStream.Close() 
End If 
End If 
End Sub