"Reference to type Routevaluedictionary claims it is defined in system.web, but it could not be found" While using Ajaxextension command

Question

The error in the title occurred in ASP.NET MVC and C#

This is the error

I want to use Ajax, but it does not work; Visual Studio does not recognize Ajax

Answer 1

I went to check many documents. As the documentation says, only works with ASP.NET MVC 5.2.