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Web Service Binding

You can load child items in a menu dynamically through a Web service. The following steps describe how to configure RadMenu so that it can use a Web service to supply child items:

  1. Add the parent items to your menu using the RadMenu Item Builder. For each item whose child items are to be added using the Web service, set its ExpandMode property to "WebService".

  2. In the properties pane for the RadMenu component, set the WebServiceSettings property to identify the Web service and service method:

  • Set the Path sub-property to the URL for the Web service.

  • Set the Method sub-property to the name of the method of the Web service that supplies child items.

  • Set the UseHttpGet sub-property to True to change the default HTTP method (POST). This property is added in Q1 2009 release

The WebServiceSettings property is global to the RadMenu object. You can't use separate methods on the Web service for different parent menu items.

  1. Optionally, set the OnClientItemPopulating property to a client-side event handler that passes context information to the Web service. The Web service can use this context information to determine what child items to return or what properties to set on those child items.

  2. Optionally, set the OnClientItemPopulated and OnClientItemPopulationFailed properties to client-side event handlers that respond when the Web service has successfully loaded child items or when the Web service has generated an error while trying to service the item request, respectively.

  3. Optionally, supply a Loading Status template by adding a LoadingStatusTemplate section to your RadMenu declaration. The Loading Status template acts as a placeholder for the group of child items while the Web service handles the request for items.

The following example shows a RadMenu that fetches all child items from a Web Service. The LoadingStatusTemplate appears while the Web service is handling the request for items.

You can obtain the parent item's Text and Value from the RadMenuItemData parameter passed to the the WebService's method. public RadMenuItemData[] GetMenuCategories( RadMenuItemData item , object context){ item.Text //returns the Text of the parent item, whose child items are being populated item.Value //returns the Value of the parent item, whose child items are being populated}

<telerik:RadMenu RenderMode="Lightweight" ID="RadMenu1" runat="server" Skin="Default">
    <WebServiceSettings Path="ProductCategories.asmx" Method="GetMenuCategories" />
        <asp:Image runat="server" ID="LoadingImage" ImageUrl="~/Ajax/Img/loading7.gif" ToolTip="Loading..."
            Width="81px" Height="21px" />
        <telerik:RadMenuItem Text="Products" Value="1" ExpandMode="WebService">
        <telerik:RadMenuItem Text="Purchase" Value="132" ExpandMode="WebService">
        <telerik:RadMenuItem Text="Support" Value="141" ExpandMode="WebService">
        <telerik:RadMenuItem Text="Community" Value="155" ExpandMode="WebService">
        <telerik:RadMenuItem Text="Corporate" Value="164" ExpandMode="WebService">

To use the integrated support, the Web service should have the following signature:

public RadMenuItemData[] GetMenuCategories(RadMenuItemData item, object context)
    DataTable productCategories = GetProductCategories(item.Value);
    List<RadMenuItemData> result = new List<RadMenuItemData>();
    foreach (DataRow row in productCategories.Rows)
        RadMenuItemData itemData = new RadMenuItemData();
        itemData.Text = row["Title"].ToString(); 
        itemData.Value = row["CategoryId"].ToString();
        if (Convert.ToInt32(row["ChildrenCount"]) > 0) 
            itemData.ExpandMode = MenuItemExpandMode.WebService;
    return result.ToArray();
Public Function GetMenuCategories(ByVal item As RadMenuItemData, ByVal context As Object) As RadMenuItemData()
    Dim productCategories As DataTable = GetProductCategories(item.Value)
    Dim result As New List(Of RadMenuItemData)()
    For Each row As DataRow In productCategories.Rows
        Dim itemData As New RadMenuItemData()
        itemData.Text = row("Title").ToString()
        itemData.Value = row("CategoryId").ToString()
        If Convert.ToInt32(row("ChildrenCount")) > 0 Then
            itemData.ExpandMode = MenuItemExpandMode.WebService
        End If
    Return result.ToArray()
End Function    

For a live example of using a Web service to populate child items, see Populating from a Web Service.

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