NodeExpand
When the user clicks the plus button next to a Node that has child Nodes, the NodeExpand event fires. Use the RadTreeNodeEventArgs.Node property to get or set the clicked-on Node properties. The Node ExpandMode property must be set to ServerSide, ServerSideCallback or WebService for this event to fire.
protected void RadTreeView1_NodeExpand(object sender, Telerik.Web.UI.RadTreeNodeEventArgs e)
{
for (int i = 1; i <= 10; i++)
{
e.Node.Nodes.Add(new Telerik.Web.UI.RadTreeNode("Child Node " + i.ToString()));
}
e.Node.ExpandMode = Telerik.Web.UI.TreeNodeExpandMode.ClientSide;
}
Protected Sub RadTreeView1_NodeExpand(ByVal sender As Object, ByVal e As Telerik.Web.UI.RadTreeNodeEventArgs)
Dim i As Integer = 1
While i <= 10
e.Node.Nodes.Add(New Telerik.Web.UI.RadTreeNode("Child Node " + i.ToString()))
System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1)
End While
e.Node.ExpandMode = Telerik.Web.UI.TreeNodeExpandMode.ClientSide
End Sub