IfcDoc.FormRule.comboBoxUsage_SelectedIndexChanged C# (CSharp) Method

        private void comboBoxUsage_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.textBoxIdentifier.Enabled = (this.comboBoxUsage.SelectedIndex > 0);
            switch(this.comboBoxUsage.SelectedIndex)
            {
                case 0:
                    this.textBoxIdentifier.Text = "";
                    this.m_rule.Identification = null;
                    this.m_rule.Description = null;
                    break;

                case 1:
                    this.m_rule.Description = "*";
                    break;

                case 2:
                    this.m_rule.Description = null;
                    break;
            }

            this.UpdateBehavior();
        }