TreeView load on demand (WCF): object reference not set..

[Nejc Žerjal]

Hi,

I use ASP.NET AJAX RadTreeView control (2009 Q3). I populate root nodes manually but for subnodes I use WCF service (to load them on demand). The problem is that the web service/method parameteres "p_Node", "p_Context" ARE ALWAYS null when method is invoked:

  [ServiceContract(Namespace = "")]
  [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
  public class TreeViewService
  {
    [OperationContract()]
    public RadTreeNodeData[] LoadChildData(RadTreeNodeData p_Node, IDictionary<string, object> p_Context)
    {
         string currentVal = p_Node.Value;  // error - null on every call
         .....
         return listOfNodes.ToArray();
    }


The service.model in web.config is defined as:

<system.ServiceModel>
   
    <!-- bindings -->
    <bindings>
      <webHttpBinding>
        <binding name="webBinding">
          <security mode="None" />
        </binding>
      </webHttpBinding>
    </bindings>
    
    
    <!-- behaviors -->
    <behaviors>
      <endpointBehaviors>
        <behavior name="ajaxBehavior">
          <enableWebScript />
        </behavior>
      </endpointBehaviors>
      <serviceBehaviors>
        <behavior name="defaultBehavior">
          <serviceDebug includeExceptionDetailInFaults="true" />
          <serviceMetadata httpGetEnabled="true" />
        </behavior>
      </serviceBehaviors>
    </behaviors>

    <!-- ASP.NET compatibility mode -->
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true" />
    
    <services>
      <!-- TreeViewService.svc -->
      <service name="TreeViewService" behaviorConfiguration="defaultBehavior">
        <host>
          <baseAddresses>
            <add baseAddress="TreeViewService.svc"/>
          </baseAddresses>
        </host>
        <endpoint address=""
                  behaviorConfiguration="ajaxBehavior"
                  binding="webHttpBinding"
                  contract="TreeViewService" />
      </service>
    </services>
    
</system.ServiceModel>


The .aspx page contains the following definition:

<telerik:RadTreeView ID="radTreeView" runat="server" OnClientNodeClicked="OnNodeClicked"
      DataFieldID="Code" EnableViewState="False" DataFieldParentID="ParentCode">
      <webservicesettings path="TreeViewService.svc" method="LoadChildData" />
      <databindings>
        <telerik:RadTreeNodeBinding Depth="0" ExpandMode="WebService" ValueField="Code" />
        </databindings>
    </telerik:RadTreeView>


What is wrong?? Thank you for help.

Regards,
Damjan

[Vesko]

I suggest to follow the steps from this help topic:

WCF Web Service Load On Demand