RadTreeView for ASP.NET AJAX Version Q3 2008 released 11/25/2008 (release history)

The ExpandAnimation and CollapseAnimation tags of the RadTreeView object control the expand/collapse animations.

For each expand or collapse animation, you can specify its Type and Duration:

• The Type is chosen from a list of predefined animation effects.
• The Duration is set in milliseconds.

To disable the animation effects, set the Type to AnimationType.None.

    <telerik:RadTreeView ID="RadTreeView1" runat="server" Skin="Vista"/>
        <ExpandAnimation Type="OutQuart" Duration="300" />
        <CollapseAnimation Type="OutQuint" Duration="200" />
        ...
    </telerik:RadTreeViewu>