About update dataset for a .RDLC file in Visual Studio 2010
In Visual Studio 2010, if you open a report template file .rdlc. sometimes you might realize you can not update dataset if your data source is changed.
The most likely reason is that you do not see the "Report Data" panel in your Visual Studio 2010, see the below screen :
IF you can not see this panel, you can open it in the "View" menu: