Asp.net mvc3 abnormal Error

Solve an error in mvc3.

'System. web. webpages. HTML. htmlhelper 'does not contain a definition for 'renderaction' and no extension method 'renderaction' accepting a first argument of type' system. web. webpages. HTML. htmlhelper 'could be found (Are you missing a using direve ve or an assembly reference ?)

If you encounter this error, you may feel very strange. Why can't the most basic methods of htmlhelper. renderaction be found. Tell you the real answer, it is because you have installed Asp.net mvc4, mvc4 will install a webpages2.0 component, resulting in a conflict, so if you encounter this error, first put ASP. mvc4 is uninstalled.