RadTreeView for ASP.NET AJAX
Contents
RadControls for ASP.NET AJAX

The OnClientNodeDropping client-side event is called before nodes are dropped and can be canceled.

The event handler receives parameters:

  1. The treeview instance that fired the event.

  2. Event arguments with functions:

    • get_destNode() retrieves a reference to the destination node, i.e. the node that is being dropped onto.

    • get_dropPosition() returns the relative position of the dropped node(s) and can be "over", "above" or "below".

    • get_htmlElement() retrieves the DOM html element representing the destination node.

    • get_sourceNode() retrieves the node being dropped.

    • get_sourceNodes() retrieves an array of nodes being dropped. It is useful when the RadTreeView MultipleSelect property is True.

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

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

The example below demonstrates preventing a node from being dropped between levels and also displays information from each of the eventArgs functions.

CopyJavaScript
<script type="text/javascript" language="javascript">

    function ClientNodeDropping(sender, eventArgs) {
        if (eventArgs.get_sourceNode().get_level() != eventArgs.get_destNode().get_level()) {
            alert("You cannot drag nodes between levels");
            eventArgs.set_cancel(true);
        }
        else {
            alert("The source node is: " + eventArgs.get_sourceNode().get_text() + "\n" +
            //if MultipleSelect = True
           "The number of source nodes: " + eventArgs.get_sourceNodes().length + "\n" +
           "The destination node is: " + eventArgs.get_destNode().get_text() + "\n" +
           "The HTML element is: " + eventArgs.get_htmlElement().innerHTML + "\n" +
           "The drop position is: " + eventArgs.get_dropPosition()
            );
        }
    }

</script>
CopyASPX
<telerik:RadTreeView ID="RadTreeView1" 
                     runat="server" 
                     EnableDragAndDrop="True" 
                     MultipleSelect="True"
                     OnClientNodeDropping="ClientNodeDropping">
</telerik:RadTreeView>