I downloaded the latest Microsoft ReportViewer from the link below and installed it. I want to be able to export (render) my Excel files in xlsx format. I’m referencing version 11.0.3366.16 of the following dll’s in my project…

Microsoft.ReportViewer.Common
Microsoft.ReportViewer.ProcessingObjectModel
Microsoft.ReportViewer.WinForms

The download link
http://www.microsoft.com/en-us/download/details.aspx?id=35747

When specifying what you want your output to be, instead of sending WORD and EXCEL as the parameters for the output, send WORDOPENXML and EXCELOPENXML for the new office version.

To verify what output your version of assemblies support, use

<ReportObjec>.LocalReport.ListRenderingExtensions

For example:
RenderingExtension[] r = reportViewer.LocalReport.ListRenderingExtensions();

The complete list is:

• Image (Tiff)
• PDF
• Excel 2003
• Excel 2007-2010
• Word
• Word 2007-2010