How to retrive value from Telerik RadComboBox in RadGrid on insert

I was having an issue getting the SelectedValue from the telerik RadComboBox control in a rad grid. Here is how you do it:

The front End code:

       <telerik:GridDropDownColumn DataSourceID="DSCategories" ListTextField="CategoryName" ListValueField="CategoryID"
                    UniqueName="CategoryDD" SortExpression="CategoryName" HeaderText="Category" DataField="CategoryID"
                    DropDownControlType="RadComboBox" FooterText="RadComboBox column footer"
                    AllowAutomaticLoadOnDemand="true" AllowVirtualScrolling="true" ShowMoreResultsBox="true"
                    ItemsPerRequest="10">
    </telerik:GridDropDownColumn>

The Backend Code:

    protected void RadGrid1_InsertCommand(object source, GridCommandEventArgs e)

 {
   GridEditFormInsertItem insertItem = e.Item as GridEditFormInsertItem;
   RadComboBox DDCat = (insertItem["CategoryDD"].Controls[0] as RadComboBox);
   int DDcategory = Convert.ToInt16(DDCat.SelectedValue);
  }