SaveFileDialog error when cancelling the save dialog box

Question

I have a button to save text files, however if the user chooses cancel in the save dialog box I get this error message:

an unhandled exception of type 'system.argumentexception' occurred in mscorlib.dll

Additional information: empty path name is not legal.

Private sub cmdSave_Click (sender As object, e As EventArgs) Handles cmdSave.Click
    If rtfTextEditor.Text.Length > 0 then
      SaveFileDialog1.ShowDialog()
      System.IO.File.WriteAllText(SaveFileDialog1.Filename, rtfTextEditor.Text)
    End If
End Sub

Answer 1

I assume SaveFileDialog1.Filename is Nothing when the dialog is cancelled.

You should check the result of the dialog:

If SaveFileDialog1.ShowDialog = DialogResult.OK Then
    System.IO.File.WriteAllText(SaveFileDialog1.Filename, rtfTextEditor.Text)
End If