在升级ASP.NET之后注册httpHandlers？

Question

I was asked to upgrade an ASP.NET web application from VS 2008 to VS 2010. After the upgrade there were a few issue that I fixed, mainly connectionStrings. But I started the application in debug mode to go through it and verify everything works. I noticed that I get a "Server Error" when clicking a link that has a report viewer.

The exact error is:

The Report Viewer Web Control HTTP Handler has not been registered in the application's web.config file.

Add <add verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=9.0.0.0, Culture=neutral, publicKeyToken=b08f5f1f11d90a3a" /> to the system.web/httpHandlers section of the web.config file.

I checked web.config and everything was the same except for version, which was 10.0.0.0. I set it to 9.0.0.0. Doing this fixes the error for all reports. But this is only a temporary solution because as soon as I open a report in design view, I am prompted to convert to RDLC 2008 format. If I convert it, I get the server error again and I get compile errors for the xml(version 1.0) files.

I'm lost at what to do to fix this. Any suggestions?

Answer 1

So I figured out that there was an issue with my Visual Studio installation. My web application worked fine, including the reports, when I would debug it. But then the reports would stop working, even reports that worked a few seconds ago. I then noticed that the web.config file had changed from

Add <add verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=9.0.0.0, Culture=neutral, publicKeyToken=b08f5f1f11d90a3a" />

TO

Add <add verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, publicKeyToken=b08f5f1f11d90a3a" />

The versions would change on there own without notification. I checked with the other programmers and they did not encounter this specific issue. So one of them suggested for me to reinstall VS 2010 and check if the issue occurs again. What do you know, the issue was resolved after reinstalling VS 2010.