Problem with empty RadComboBoxContext

[Jevgenij]

Hi all,

I'm facing the problem while using the RadComboBox. I've used the example from Telerik Demo to populate RadComboBox with data on demant in a new empty project. And when the control calls for the WCF service for data the RadComboBoxContext parameter is empty.
Can you please advice me what I'm doing wrong?

ASPX code:

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"

    CodeBehind="Default.aspx.cs" Inherits="WebApplication1._Default" %>

    <%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI" %>   

<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">

</asp:Content>

<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">

      <div>

        <telerik:RadScriptManager ID="RadScriptManager1" runat="server">

        </telerik:RadScriptManager>

 

        <telerik:RadComboBox runat="server" ID="RadComboBox1" Height="100px"

            EnableLoadOnDemand="true" ShowMoreResultsBox="true" EnableVirtualScrolling="true"

            EmptyMessage="Type here ...">

            <WebServiceSettings Path="~/ComboBoxWcfService.svc" Method="LoadData" />

        </telerik:RadComboBox>

    </div>

    <asp:LinqDataSource ID="LinqDataSource1" runat="server">

</asp:LinqDataSource>

</asp:Content>

WCF code:

[ServiceContract(Namespace = "")]

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]

public class ComboBoxWcfService {

    public void DoWork()

    {

    }

    [OperationContract]

    public RadComboBoxData LoadData(RadComboBoxContext context)

    {

        //The RadComboBoxData object contains all required information for load on demand:

        // - the items

        // - are there more items in case of paging

        // - status message to be displayed (which is optional)

 

        AdventureWorksDataContext northwind = new AdventureWorksDataContext();

 

 

         

        RadComboBoxData result = new RadComboBoxData();

 

        //Get all items from the Customers table. This query will not be executed untill the ToArray method is called.

        var allCustomers = from customer in northwind.Customers

                           orderby customer.ContactName

                           select new RadComboBoxItemData

                           {

                               Text = customer.ContactName

                           };

 

 

        //In case the user typed something - filter the result set

        string text = context.Text;

        if (!String.IsNullOrEmpty(text))

        {

            allCustomers = allCustomers.Where(item => item.Text.StartsWith(text));

        }

        //Perform the paging

        // - first skip the amount of items already populated

        // - take the next 10 items

        int numberOfItems = context.NumberOfItems;

        var customers = allCustomers.Skip(numberOfItems).Take(10);

 

        //This will execute the database query and return the data as an array of RadComboBoxItemData objects

        result.Items = customers.ToArray();

 

 

        int endOffset = numberOfItems + customers.Count();

        int totalCount = allCustomers.Count();

 

        //Check if all items are populated (this is the last page)

        if (endOffset == totalCount)

            result.EndOfItems = true;

 

        //Initialize the status message

        result.Message = String.Format("Items <b>1</b>-<b>{0}</b> out of <b>{1}</b>",

                                       endOffset, totalCount);

 

        return result;

    }

}

WebConfig:

<service behaviorConfiguration="metadataAndDebug" name="WebApplication1.ComboBoxWcfService">
  <endpoint address="" behaviorConfiguration="WebBehavior" binding="webHttpBinding"
    contract="WebApplication1.ComboBoxWcfService" />
  <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
</service>

[Ivana]

Hi Jevgenij,

The following help article explains how to create load on demand RadComboBox which loads its items from a WCF service: [http://www.telerik.com/help/aspnet-ajax/combobox-load-on-demand-wcf-service.html]. Take a look at it and see if it will help.

All the best,
Ivana
the Telerik team

[Jevgenij]

The link you provided helped me to understand where the problem was - I should have used Ajax-enabled WCF.
I had to use AjaxBehavior instead of WebBehavior:

    <behavior name="AjaxBehavior">
      <enableWebScript />
    </behavior>
    <behavior name="WebBehavior">
      <webHttp />
    </behavior>

Thank you very much for your help!