SuperPutty.dlgEditSession.textBoxHostname_Validating C# (CSharp) Method

        private void textBoxHostname_Validating(object sender, CancelEventArgs e)
        {
            if (string.IsNullOrEmpty((string)this.comboBoxPuttyProfile.SelectedItem) &&
                string.IsNullOrEmpty(this.textBoxHostname.Text.Trim()))
            {
                if (sender == this.textBoxHostname)
                {
                    this.SetError(this.textBoxHostname, "A host name must be specified if a Putty Session Profile is not selected");
                }
                else if (sender == this.comboBoxPuttyProfile)
                {
                    this.SetError(this.comboBoxPuttyProfile, "A Putty Session Profile must be selected if a Host Name is not provided");
                }
            }
            else
            {
                this.SetError(this.textBoxHostname, String.Empty);
                this.SetError(this.comboBoxPuttyProfile, String.Empty);
            }
        }