RadTreeView provides support for RTL languages.
RadTreeView considers the direction attribute set to the control itself or any parent
HTML element. If you set the direction of the body tag (or any other parent element
that contains the control) to rtl, RadTreeView reverses the node
order and aligns itself to the right side of the container.
<telerik:RadTreeView ID="RadTreeView1" runat="server" dir="rtl" ... />