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Editorial Team
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Asked: 2026-05-13T05:34:07+00:00

We are having a strange issue with the Visual Studio 2008 ReportViewer control. Specifically,

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We are having a strange issue with the Visual Studio 2008 ReportViewer control. Specifically, when we have a child control on a page, and the child control itself hosts a report viewer, and the report has a document map, the postback on the show/hide document map button seems to be lost, so the document map never disappears. I played with IPostBackEventHandler and didn’t seem to get anywhere; the ReportViewer itself implements that interface so I didn’t think I cared. Anyway, here’s the code:

Default.aspx:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="ReportViewerDocumentMapButtonStrippedExample._Default" %>

<!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 runat="server" id="div">

    </div>
    </form>
</body>
</html>

Default.aspx.cs:

using System;

namespace ReportViewerDocumentMapButtonStrippedExample {
    public partial class _Default : System.Web.UI.Page {
        protected void Page_Load(object sender, EventArgs e) {
        }

        protected override void CreateChildControls() {
            base.CreateChildControls();
            FindControl("div").Controls.Add(new rvControl());
        }
    }
}

rvControl.cs:

using System.Collections.Generic;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using Microsoft.Reporting.WebForms;

namespace ReportViewerDocumentMapButtonStrippedExample {
    public class rvControl : HtmlGenericControl {

        protected override void CreateChildControls() {
            base.CreateChildControls();
            var rvMain = new ReportViewer {
                EnableViewState = true,
                ProcessingMode = ProcessingMode.Remote,
                ShowRefreshButton = false,
                AsyncRendering = true,
                Width = new Unit(100, UnitType.Percentage),
                Height = new Unit(2000, UnitType.Pixel),
                ShowCredentialPrompts = false,
                ID = "viewer",
            };
            rvMain.ServerReport.ReportPath = "/some/report/name";
            Controls.Add(rvMain);
        }

    }
}

Anyone have an idea on this?

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1 Answer

  1. Editorial Team

    Microsoft found the answer for us. Basically, it was some confusion in ReportViewer control and the control lifecycle. The fix is a simple addition to the custom control:

    public override System.Web.UI.ControlCollection Controls {
    get {
        this.EnsureChildControls();
        return base.Controls;
    }
}
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