ReportViewer control returns blank page

asp.netreporting-servicesreportviewer

I'm having problems with the standard ASP.NET ReportViewer control (v11, SQL 2012, VS 2012). This was previously working at some point, connecting to a remote SSRS server, but during the development of the site something's broken it and I'm struggling to isolate the cause.

If I create a simple form:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ReportTest.aspx.cs" Inherits="ReportTest" %>

<%@ Register Assembly="Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" Namespace="Microsoft.Reporting.WebForms" TagPrefix="rsweb" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        This is a test!

        <rsweb:ReportViewer ID="ReportViewer1" runat="server" ProcessingMode="Remote">
            <ServerReport ReportPath="/Reports/MyTestReport" ReportServerUrl="http://sqlserver/reportserver" />           
        </rsweb:ReportViewer>
    </div>
    </form>
</body>
</html>

.. and run this, nothing is displayed on the browser. Not even the This is a test! text, which would indicate to be that something is "crashing" on the server side. Backing up this theory, using Fiddler I can see there is no attempt to contact the report server.

I've turned on all exception trapping in Visual Studio, but nothing catches and there's nothing obvious that I can see in the output. The ReportViewer control displays correctly in Design mode, and I've reinstalled the ReportViewer redistributables.

Best Answer

I've found the issue, or rather two issues:

  • I needed to have a ScriptManager on the page. Creating a completely new project with the above test webpage threw the error about the ScriptManager requirement, although a test page in the original project (and indeed, my original production page) didn't complain about the missing ScriptManager. I must have deleted the original ScriptManager by mistake. To fix it, all I needed to add was:

    <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>

  • Secondly - and this was in the production code itself - I had the parameter

    ShowParameterPrompts="True"

    With this option defined, the page wouldn't load, giving the same error as above. However, removing that option allowed the page to load normally.

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