Can I create a usercontrol that is available only inside a template?

Anyone have an idea how I can create a usercontrol that is only avail开发者_如何学Pythonable inside the template of another user control? The best example I can think of is the PostBackTrigger and AsyncPostbackTrigger. These "controls" are only available inside the Triggers "template" of the UpdatePanel. Basically, I want to be able to include placeholder elements inside of the template that are then rendered into a seperate usercontrol using only the attributes assigned in the aspx portion of the page.

an example to try and make things more clear:

<usercontrol1>
    <mytemplate>
        <table>
            <tr>
                <td><usercontrol2 ID="uc2" runat="server" Text="Text" Width="200" />
            </tr>
        </table>
    </mytemplate>
</usercontrol1>

In this example, usercontrol2 would not show up in Intellisense unless I was typing inside usercontrol1's template.

Sadly this cannot be done with User Controls. In order to do this you will have to build a templated server control.

Or using Templated User Controls per Kbrimington