Structure
The structure of the RadMenu control is as follows:
The menu consists of a hierarchy of items. The items on one level are exposed when the parent item on the previous level is expanded. Each Item is represented by a RadMenuItem instance.
At the top level are the root items. These items are always visible. They are available using the Items property of the menu control (RadMenu.Items).
Each root item may have, nested within it, a set of child items. Children of the root items are considered level 1 items. They are available using the Items property of the root item (RadMenuItem.Items)
Child items may have, nested within them, their own sets of child items. Children of level 1 items are considered level 2 items; children of level 2 items are considered level 3 items; and so on.
If the items are created at design time, the hierarchy is reflected in the ASP.NET declaration of the menu:
<telerik:RadMenu RenderMode="Lightweight" ID="RadMenu1" runat="server" Flow="Horizontal">
<Items>
<telerik:RadMenuItem runat="server" Text="Root Item 1">
<Items>
<telerik:RadMenuItem runat="server" Text="Child Item 1">
<Items>
<telerik:RadMenuItem runat="server" Text="Child Item 1.1" />
<telerik:RadMenuItem runat="server" Text="Child Item 1.2" />
</Items>
</telerik:RadMenuItem>
<telerik:RadMenuItem runat="server" Text="Child Item 2" />
</Items>
</telerik:RadMenuItem>
<telerik:RadMenuItem runat="server" Text="Root Item 2">
<Items>
<telerik:RadMenuItem runat="server" Text="Child Item 2.1" />
</Items>
</telerik:RadMenuItem>
</Items>
</telerik:RadMenu>