ASPxClientTreeView.ExpandedChanged Event
Fires on the client side after a node’s expansion state has been changed by end-user interaction.
Declaration
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";
}
}
}
}