Here is my Auto Complete RadCombobox with CSLA NameValueList<key,value> binding: <all is working well excepts it is not showing the value why? I try to play with SelectedValue and SelectedItem not working>

<telerik:RadComboBox
                                    telerik:StyleManager.Theme="{Binding ThemeManager.Theme, Source={StaticResource MyThemeStyleManager}}"
                                VerticalAlignment="Top" HorizontalAlignment="Left"
                                    MinWidth="200"
                                    Background="Transparent"  
                                     
                                    DisplayMemberPath="Value"
                                    ItemsSource="{Binding EmployeeList_Filter}"
                                    SelectedValuePath="{Binding Key, Mode=TwoWay}"
                                    Height="25"
                                    BorderBrush="Black"
                                    BorderThickness="1"
                                    DropDownClosed="RadComboBox_DropDownClosed"
                                        IsEditable="False"
                                        telerik:TextSearch.TextPath="Value"
                                        TextSearchMode="StartsWith"
                                        CanKeyboardNavigationSelectItems="True"
                                        IsMouseWheelEnabled="True"
                                        StaysOpenOnEdit="True"
                                        OpenDropDownOnFocus="True"
                                        VirtualizingStackPanel.VirtualizationMode="Recycling"
                                        
                                     
                                    />

what event is called when the item-source is finished with its loading?

want to add someting like this ValueMemberPath="Key" then it will work.

this done the trick
                                    ...
                                     ItemsSource="{Binding Model.EmployeeList_Filter}"
                                     SelectedValue="{Binding Model.EmployeeID, Mode=TwoWay}"
                                     SelectedValuePath="Key"
                                     DisplayMemberPath="Value"
                                     />