RadWindow Modal Ajax Popup hide and show from code behind

I really need some help with this. I need to, using a RadWindow control, pop up a modal window containing a dynamically populated CheckBoxList based on user selection on dropdownlist changed. Please help with any sample or information to help me achieve this.

 <telerik:RadWindow ID="UserListDialog" runat="server" Title="Editing record" Width="250"         Height="536" VisibleOnPageLoad="false" Modal=true Behaviors="Minimize, Move, Resize,Maximize" Left="580" Top="-8" EnableShadow="true">
            <ContentTemplate>
                <div style="text-align: center;">
 L开发者_Python百科IST OF STUFF TO DISPLAY 
                </div>
            </ContentTemplate>
        </telerik:RadWindow>

When using ContentTemplate, RadWindow behaves and can be used just like any other standard INamingConatiner.

For more details, check the help article and the demo on the subject.