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ASPxClientTreeView.ExpandedChanged Event

Fires on the client side after a node’s expansion state has been changed by end-user interaction.

#Declaration

TypeScript
ExpandedChanged: ASPxClientEvent<ASPxClientTreeViewNodeEventHandler<ASPxClientTreeView>>

#Event Data

The ExpandedChanged event's data class is ASPxClientTreeViewNodeEventArgs. The following properties provide information specific to this event:

Property Description
node Gets a node object related to the event.

#Remarks

Write a ExpandedChanged event handler to perform specific actions on the client side each time a node’s expansion state has been changed by end-user interaction. You can use the event parameter’s ASPxClientTreeViewNodeEventArgs.node property to identify the node which has been expanded or collapsed. If a node’s expansion state has been changed programmatically, the ExpandedChanged event does not fire.

#Example

The code below demonstrates how you can define node images and change them, when expanding and collapsing nodes on the client side.

using DevExpress.Web.ASPxTreeView;

public partial class _Default : System.Web.UI.Page {
    protected void Page_Load(object sender, EventArgs e) {
       DataBind();
       DefineImages(ASPxTreeView1.Nodes);
    }
    protected void DefineImages(TreeViewNodeCollection nodes) {
        foreach (TreeViewNode node in nodes) {
            if (node.Nodes.Count > 0) {
                node.Image.Url = "~/Images/closed_folder.png";
                DefineImages(node.Nodes);
            }
            else {
                node.Image.Url = "~/Images/file.png";
            }
        }
    }
}
See Also