We are using WinForms Reoprt viewer control. Everything worked fine until we migrated to VS2010 from VS2008. VS2010 converts our project to corresponding version simultaneously changing the version of Microsoft.ReportViwer.Common and Microsoft.WinForms from 9.0 to 10.0. Also during the first opening of .rdlc file VS2010 suggests to convert it.
After such manipulation report crashes and displays the following error:
"An error occured during local report processing. An error has occured during report processing. The Group expression used in Groping '' returned a data type that is not valid."
However if I change assemblies version back to 9.0 everithing works fine.
Does anybody have any idea or help how to make it work with newer libraries?
I've found the solution. This problem was with nested field attributes and fixed in VS2010 SP1. This article explains this issue http://blogs.msdn.com/b/brianhartman/archive/2010/10/27/nested-objects-in-local-mode.aspx