OnClientNodeExpanding

The OnClientNodeExpanding client-side event occurs when the user clicks the expand (plus) button. The event is called just prior to postback or URL redirection and can be canceled.

Calling the client-side expand() or set_expanded(true) method does not fire OnClientNodeExpanding and OnClientNodeExpanded client-side events. More information is available here.

The event handler receives parameters:

1. The TreeView instance that fired the event.

2. Event arguments with functions:

• get_node() retrieves a reference to the clicked on node.

• set_cancel() - call this function to specify whether the event should be canceled (true) or not (false).

• get_domEvent() retrieves a DOM event object of the node expand.

The example below shows how to prevent expanding a "Recent Searches" node. Note that the OnClientNodeExpanded event does not fire when the expand (plus) button is clicked.

ASPNET

<telerik:RadTreeView RenderMode="Lightweight" ID="RadTreeView1" runat="server" AllowNodeEditing="True" 
                     OnClientNodeExpanded="ClientNodeExpanded"
                     OnClientNodeExpanding="ClientNodeExpanding">
</telerik:RadTreeView>

JavaScript

function ClientNodeExpanded(sender, eventArgs)
{
	alert("OnClientNodeExpanded");
}
function ClientNodeExpanding(sender, eventArgs)
{

	var node = eventArgs.get_node();    
	if(node.get_text() == "Recent Searches")
	{
		eventArgs.set_cancel(true);
	}
}  

See Also

• OnClientNodeExpanded

• RadTreeNode

• Expanding Nodes