Microsoft Report Viewer 2012 update: a ‘gotcha’ to be aware of

Something which I have been waiting for a long time has finally been released! The ReportViewer 2012 redistributable RTM package is available for download now!

Deployment notes

FYI, ReportViewer is used by Management Studio (SSMS), other utilities and also by any custom application which uses this to render local RDLC reports, or within a web application to view remotely rendered reports.

SQL 2012 installation deploys ReportViewer if the Management Tools are selected for installation. The other shipping vehicle for the ReportViewer control is Visual Studio 2012. This blog post pertains more to the case where we installed ReportViewer through the normal SQL 2012 installer.

FYI, you can view the ReportViewer 2012 assembly version at C:windowsassemblyGAC_MSILMicrosoft.ReportViewer.WinForms11.0.0.0__….. Right clicking on the assembly, and viewing the Details tab will give you the version of the DLL.

Note the ‘gotcha’

Now, the updated runtime release will deploy the equivalent of SQL 2012 SP1 binaries, so you get the latest and greatest bits! These should deploy a 11.0.3010 version for the Microsoft.ReportViewer.WinForms.dll file (and other files as well.)

Now, here’s the ‘note from the field’ thing which you can only get from me Smile If you just install SQL 2012 SP1 (without later running the above download) it does not seem to update the ReportViewer control. Normally this may not have much visible impact, but if you are like me, you may want to keep the runtime up to date due to the number of important fixes in such updated versions.

Test case

In my tests, just applying SQL 2012 SP1 installation did NOT upgrade the runtime to 11.0.3000. It was still at 11.0.2100. However, applying the above updated runtime MSI will upgrade the runtime to 11.0.3010.

Your checkpoint is that the version of ReportViewer 2012 assembly under C:windowsassemblyGAC_MSILMicrosoft.ReportViewer.WinForms11.0.0.0__….. should finally be 11.0.3010 or higher. (repeat this check for the other controls such as Microsoft.ReportViewer.WebForms as well.


So in short, if you use ReportViewer – either indirectly (like in SSMS) or directly (through custom applications developed using Visual Studio 2012) it is highly recommended to update your RTM ReportViewer 11.0 runtime to the latest version using the MSI from the download link.

Reportviewer and drillthrough

I was doing some testing the other day with a ReportViewer control hosted in a WinForms application to do local mode report processing. As some of my reports had a drillthrough / navigation option set, I had setup a set of DrillthroughEventHandler to ensure that the right datasources are bound to the report when the drillthrough reports are invoked.

The problem in my case was that on specific reports being invoked, the drillthrough would cause an exception inside ReportViewer and it would display:

An error occurred during rendering of the report.
Object reference not set to an instance of an object.

If this issue was random I would have suspected issues like the one in but I was able to get this error consistently. On later troubleshooting it was clear that:

  • I had two DrillthroughEventHandler setup, but only one for each report should have been ‘active’.
  • Unfortunately the way you setup these handlers is you use the following construct:

reportViewer1.Drillthrough += new DrillthroughEventHandler(CorrectDrillthroughEventHandler)

  • Due to the way my code was structured, it turned out I would add the 2nd DrillthroughEventHandler to a report which never really needed it. So I ended up making sure that the unwanted handlers were registered first, just before the call to the registration of the correct one.

reportViewer1.Drillthrough -= new DrillthroughEventHandler(UnwantedDrillthroughEventHandler);

Doing this got rid of the exception and things worked fine for me. Of course, be sure that this is not the ONLY reason for the above exception. This was a specific case and I hope it might prove useful for someone who is using Drillthrough and multiple DrillthroughEventHandler.

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