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Using RadXmlHttpPanel with RadAjaxPanel

Customers by Countries
Order IDOrder DateShip NameShip CityShip Country
12345678910...
 Page 1 of 76, items 1 to 10 of 760.
103059/13/1996 12:00:00 AMOld World DelicatessenAnchorageUSA
103079/17/1996 12:00:00 AMLonesome Pine RestaurantPortlandUSA
103149/25/1996 12:00:00 AMRattlesnake Canyon Grocery italy
103159/26/1996 12:00:00 AMIsland TradingCowesUK
103179/30/1996 12:00:00 AMLonesome Pine RestaurantPortlandUSA
1031910/2/1996 12:00:00 AMTortuga RestauranteMéxico D.F.Mexico
1032110/3/1996 12:00:00 AMIsland TradingCowesUK
1032310/7/1996 12:00:00 AMKöniglich EssenBrandenburgGermany
1032410/8/1996 12:00:00 AMSave-a-lot MarketsBoiseUSA
1032510/9/1996 12:00:00 AMKöniglich EssenBrandenburgGermany

The following example demonstrates how to benefit by using the RadAjaxPanel combined with the RadXmlHttpPanel.

A RadGrid is hosted in a RadXmlHttpPanel, and the RadXmlHttpPanel itself is wrapped by a RadAjaxPanel. The RadXmlHttpPanel populates the RadGrid by loading on-demand content, while the RadAjaxPanel ensures that all of the (RadGrid's) events are fired correctly and trigger Ajax partial updates. This way we have optimum performance and take full advantage of what each panel does best.

Note: RadGrid's Insert/Update/Delete operations are not supported in this scenario (RadXmlHttpPanel in RadAjaxPanel), because they rely heavily on the ViewState. Since the ViewState is not updated on ASP.NET client callbacks, on the next row Insert/Update/Delete the incorrect row will be affected, and this will cause data inconsistency. That's why this setup should be used in simpler scenarios, where the ViewState is not that important.

  • DefaultVB.aspx
  • DefaultVB.aspx.vb
  • scripts.js
<%@ Page Language="vb" AutoEventWireup="true" Inherits="Telerik.Web.Examples.XmlHttpPanel.GridInXmlHttpPanel.DefaultVB"CodeFile="DefaultVB.aspx.vb"  %>

<!DOCTYPE html>
<html xmlns='http://www.w3.org/1999/xhtml'>
<head runat="server">
    <title>Telerik ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
    <telerik:RadScriptManager runat="server" ID="RadScriptManager1" />
    <telerik:RadSkinManager ID="RadSkinManager1" runat="server" ShowChooser="true" />
    <div class="demo-container">
        <div style="margin-bottom: 10px;">
            <span style="margin-right: 15px;">Customers by Countries</span>
            <telerik:RadComboBox RenderMode="Lightweight" ID="RadComboBox1" runat="server" OnClientSelectedIndexChanged="telerikDemo.setValue"
                AllowCustomText="true" Filter="Contains" DataSourceID="SqlDataSource1" DataTextField="Country" EmptyMessage="Choose a country..."
                Style="">
            </telerik:RadComboBox>
        </div>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
            SelectCommand="SELECT DISTINCT [Country] FROM [Customers] Order By [Country]"></asp:SqlDataSource>
        <telerik:RadAjaxPanel ID="RadAjaxPanel1" runat="server">
            <telerik:RadXmlHttpPanel ID="RadXmlHttpPanel1" runat="server" EnableClientScriptEvaluation="true"
                OnServiceRequest="XmlHttpPanel1_ServiceRequest" RenderMode="Block">
                <telerik:RadGrid RenderMode="Lightweight" ID="RadGrid1" runat="server" OnNeedDataSource="RadGrid1_NeedDataSource"
                    Width="100%" AllowSorting="True" PageSize="10" AllowPaging="True" AllowMultiRowSelection="True"
                    GridLines="None">
                    <PagerStyle Mode="NumericPages"></PagerStyle>
                </telerik:RadGrid>
            </telerik:RadXmlHttpPanel>
        </telerik:RadAjaxPanel>
    </div>
    <script src="scripts.js" type="text/javascript"></script>
    <telerik:RadScriptBlock ID="RadScriptBlock1" runat="server">
        <script type="text/javascript">
            Sys.Application.add_load(function() {
                telerikDemo.radXmlHttpPanel = $find("<%=RadXmlHttpPanel1.ClientID %>");
            });
        </script>
    </telerik:RadScriptBlock>
    </form>
</body>
</html>

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