Solved: Unable to export ASPxGridView in UpdatePanel

If you want to export your ASPxGridView in UpdatePanel by using a DevExpress control, ASPxGrivViewExporter, you will need this trick.

In order to perform the export, use the following code template.

Default.aspx

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true"
    CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register Assembly="DevExpress.Web.v11.1, Version=11.1.7.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a"
    Namespace="DevExpress.Web.ASPxMenu" TagPrefix="dx" %>
<%@ Register Assembly="DevExpress.Web.ASPxGridView.v11.1.Export, Version=11.1.7.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a"
    Namespace="DevExpress.Web.ASPxGridView.Export" TagPrefix="dx" %>
<%@ Register Assembly="DevExpress.Web.ASPxGridView.v11.1, Version=11.1.7.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a"
    Namespace="DevExpress.Web.ASPxGridView" TagPrefix="dx" %>
<%@ Register Assembly="DevExpress.Web.ASPxEditors.v11.1, Version=11.1.7.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a"
    Namespace="DevExpress.Web.ASPxEditors" TagPrefix="dx" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <dx:ASPxPopupMenu ID="ASPxPopupMenu1" runat="server" ClientInstanceName="popupMenu"
                OnItemClick="ASPxPopupMenu1_ItemClick">
                <items>
<dx:MenuItem Text="WriteXlsToResponse">
</dx:MenuItem>
</items>
            </dx:ASPxPopupMenu>
            <dx:ASPxGridView ID="ASPxGridView1" runat="server" AutoGenerateColumns="False" ClientInstanceName="grid"
                DataSourceID="AccessDataSource1" EnableCallBacks="false" KeyFieldName="CategoryID">
                <clientsideevents contextmenu="function(s, e) {
popupMenu.ShowAtPos(ASPxClientUtils.GetEventX(e.htmlEvent), ASPxClientUtils.GetEventY(e.htmlEvent));
}" />
                <columns>
<dx:GridViewDataTextColumn FieldName="CategoryID" ReadOnly="True" VisibleIndex="0">
<EditFormSettings Visible="False" />
</dx:GridViewDataTextColumn>
<dx:GridViewDataTextColumn FieldName="CategoryName" VisibleIndex="1">
</dx:GridViewDataTextColumn>
<dx:GridViewDataTextColumn FieldName="Description" VisibleIndex="2">
</dx:GridViewDataTextColumn>
</columns>
            </dx:ASPxGridView>
            <dx:ASPxGridViewExporter ID="ASPxGridViewExporter1" runat="server" GridViewID="ASPxGridView1">
            </dx:ASPxGridViewExporter>
            <dx:ASPxButton ID="ASPxButton1" runat="server" Text="WriteXlsToResponse PostBackTrigger"
                OnClick="ASPxButton1_Click">
            </dx:ASPxButton>
            <asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="~/App_Data/nwind.mdb"
                SelectCommand="SELECT [CategoryID], [CategoryName], [Description] FROM [Categories]"></asp:AccessDataSource>
        </ContentTemplate>
        <Triggers>
            <asp:PostBackTrigger ControlID="ASPxButton1" />
        </Triggers>
    </asp:UpdatePanel>
</asp:Content>

Default.aspx.cs

using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Init(object sender, EventArgs e)
    {
        DevExpress.Web.ASPxClasses.ASPxWebControl.RegisterBaseScript(Page);//ASPxClientUtils
        RegisterPostBackControl();
    }
    private void RegisterPostBackControl()
    {
        ScriptManager sm = (ScriptManager)Page.Master.FindControl("ScriptManager1");
        sm.RegisterPostBackControl(ASPxPopupMenu1);
    }
    protected void ASPxPopupMenu1_ItemClick(object source, DevExpress.Web.ASPxMenu.MenuItemEventArgs e)
    {
        ASPxGridViewExporter1.WriteXlsToResponse();
    }
    protected void ASPxButton1_Click(object sender, EventArgs e)
    {
        ASPxGridViewExporter1.WriteXlsToResponse();
    }
}

MasterPage.master

<%@  Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="MasterPage" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
        <div>
            <asp:ScriptManager ID="ScriptManager1" runat="server">
            </asp:ScriptManager>
            <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
            </asp:ContentPlaceHolder>
        </div>
    </form>
</body>
</html>

If you get “Object reference not set to an instance of an object” error on the line sm.RegisterPostBackControl(ASPxPopupMenu1);, make sure you put your ScriptManager right below of form tag in your Root.master.