R – ASP.NET ReportViewer local mode performance (expression_host regeneration)

I already found a solution. On the reportviewer control you can signify to execute the report in an so-called sandbox app-domain:

`rpv1.LocalReport.ExecuteReportInSandboxAppDomain();`

This will not prevent the creation of the Expression_Host assemblies because these are necessary to evaluate the expressions you have used in your report. It will however start the report in a new application domain. That new application domain is then unloaded after the report is finished and as a result, any loaded assembly in that domain is also unloaded.

The solution is actually some of the ReportViewer JavaScript causes an infinite loop in Chrome, I am posting the source code on how to solve this issue by making a custom version of the ReportViewer control and fixing the broken JavaScript (I've lost the link to the solution, but I didn't write this, just used it :))

I can confirm that now we have upgraded to the newest ReportViewer in Visual Studio 2010, the Chrome CPU issue no longer exists and this work around isn't required.

public class MyReportViewer : Microsoft.Reporting.WebForms.ReportViewer
{
    protected override void Render(HtmlTextWriter writer)
    {
        using (StringWriter sw = new StringWriter())
        {
            HtmlTextWriter tmpWriter = new HtmlTextWriter(sw);
            base.Render(tmpWriter);
            string val = sw.ToString();
            val = val.Replace(@"!= 'javascript:\'\''", @"!= 'javascript:\'\'' && false");
            writer.Write(val);
        }
    }
}