Accessing a RadTreeView Embedded in Another Control
To find a RadTreeView client-side instance when embedded in another control, use server side functionality to locate the RadTreeView ClientID. In the following example the RadTreeView is embedded in a RadMenu item template.
<telerik:RadMenu RenderMode="Lightweight" ID="RadMenu1" runat="server">
<ItemTemplate>
<telerik:RadTreeView RenderMode="Lightweight" ID="RadTreeView1" runat="server">
</telerik:RadTreeView>
</ItemTemplate>
</telerik:RadMenu>
var tree = $find('<%=RadMenu1.Items[0].FindControl("RadTreeView1").ClientID %>');