<telerik:RadTreeView runat="server" ID="RadTreeView1" DataTextField="SearchKeyword"
DataValueField="id" LoadingStatusPosition="AfterNodeText" OnClientNodePopulating="nodePopulating" >
function onSuccess(result, node) {
debugger;
node.hideLoadingStatus();
//the result in JSON format is available as a "d" field
var data = result.d;
//Traverse the array of objects and create combobox items
for (var i = 0; i < data.length; i++) {
var dataItem = data[i];
var childNode = new Telerik.Web.UI.RadTreeNode();
childNode.set_text(dataItem.Text);
childNode.set_value(dataItem.id);
childNode.set_expandMode(Telerik.Web.UI.TreeNodeExpandMode.WebService);
node.get_nodes().add(childNode);
}
node.set_expandMode(Telerik.Web.UI.TreeNodeExpandMode.ClientSide);
node.expand();
}
function nodePopulating(sender, args) {
debugger;
var node = args.get_node();
node.showLoadingStatus(sender.get_loadingMessage(), sender.get_loadingStatusPosition());
//get only the child nodes of the current node
var filter = "&$filter=parentId eq " + node.get_value();
//Call the ADO.NET Data Service
$telerik.$.ajax({
type: "GET", // HTTP method
url: '<%= ResolveUrl("TreeViewAdoNetService.svc/Links?") %>' + filter, // ADO.NET DataService URL
contentType: "application/json; charset=utf-8", //request the result to be in JSON
dataType: "json",
success: function(result) { //callback method to invoke when the request is complete
onSuccess(result, node);
}
});
args.set_cancel(true);
}