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WCF Service Binding

As of Q1 2009, RadTreeView supports load on demand from WCF service.

The steps below show how to load the nodes of RadTreeView from WCF service. It shows how to use the context object to pass information from the client to the OperationContract. We will set additional Attributes for every node (in addition to the Text and Value properties) so we can see how to use them in the OnClientNodeDataBound event.

  1. Create a new Web Site in Visual Studio. Make sure the target framework is set to 3.5

  2. Drag RadTreeView from your toolbox. From the SmartTag click on the Add RadScriptManager link. It will automatically register the handler in the web.config file RadTreeView Smart Tag RadTreeView Handler Added

  3. Add the WCF service – right click on your project in Solution Explorer and select Add New Item. This is important: select the Ajax-enabled WCF service option (do not mix it with WCF Service):

    RadTreeView Adding WCF Service

    Clicking the Add button will create the .svc file as well as the code behind file placed in the App_Code folder. The web.config file is also automatically updated with the appropriate system.serviceModel node:

        <behavior name="ServiceAspNetAjaxBehavior">
          <enableWebScript />
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true" />
      <service name="Service">
        <endpoint address="" behaviorConfiguration="ServiceAspNetAjaxBehavior" binding="webHttpBinding" contract="Service" />

    These settings are important . If you don't have them correct - you might receive a JavaScript error: Method "MethodName" Failed.

  4. Open the Service.cs file and add the method which will return the TreeView nodes.

      [ServiceContract(Namespace = "")]
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class Service
        public RadTreeNodeData[] GetData(RadTreeNodeData node, IDictionary<string, object> context)    
            List<RadTreeNodeData> nodes = new List<RadTreeNodeData>();
            string productsSuite = context["ProductSuite"].ToString();
            List<String> radControls = new List<string>() 
            foreach (string radControl in radControls)        
                RadTreeNodeData node = new RadTreeNodeData() 
                    Text = string.Format("{0} for {1}", radControl, productsSuite),               
                    Value = radControl,
                    //set the attribute of the item which will be used in the ClientDataBound event           
                    Attributes = new Dictionary<string, object> { { "ToolTip", radControl } }            
            return nodes.ToArray();    

Note that the above code uses the context object which passes the information of the selected RadioButton on the page and is set in the OnClientNodePopulating event.

You can set additional attributes to every node by using the Attributes collection. Later, you can read these attributes in OnClientNodeDataBound or OnClientNodePopulated event.

function OnClientNodePopulatingHandler(sender, e) {
    var context = e.get_context();
    //using jQuery to get the checked item and pass it to the server       
    context["ProductSuite"] = $telerik.$("input[name='rblSuites']:checked").val();

function OnClientNodeDataBoundHandler(sender, e) {
    var node = e.get_node();
    //set the ToolTip based on the attribute

Here is the TreeView declaration:

<asp:RadioButtonList ID="rblSuites" runat="server">
    <asp:ListItem Selected="True">ASP.NET AJAX</asp:ListItem>
<telerik:RadTreeView RenderMode="Lightweight" runat="server" ID="RadTreeView1" OnClientNodePopulating="OnClientNodePopulatingHandler"
        <telerik:RadTreeNode Text="Products" ExpandMode="WebService">
    <WebServiceSettings Path="Service.svc" Method="GetData" />

and the result:

RadTreeView WCF Web Service Result

See Also

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