IfcDoc.FormParameters.comboBoxTemplate_SelectedIndexChanged C# (CSharp) Method

        private void comboBoxTemplate_SelectedIndexChanged(object sender, EventArgs e)
        {
            DocModelRuleEntity sel = this.comboBoxTemplate.SelectedItem as DocModelRuleEntity;
            if (sel == null)
                return;

            if (sel.References.Count > 0)
            {
                DocTemplateDefinition docTemplateInner = sel.References[0];
                DocTemplateUsage docConceptInner = ((DocTemplateItem)this.ConceptItem).RegisterParameterConcept(this.ConceptAttr.Identification, docTemplateInner);
                this.ConceptLeaf = docConceptInner;
            }
        }