'Ajax' does not exist in the namespace 'System.Web.Mvc'

ajax asp.net-mvc asp.net-mvc-5
Mike van L picture Mike van L · Nov 7, 2014 · Viewed 54.2k times · Source

I'm new to ASP.NET MVC 5 and I wanted to build a small project to figure some things out. When i opened the project in the browser I got an error saying:

Compiler Error Message: CS0234: The type or namespace name 'Ajax' does not exist in the namespace 'System.Web.Mvc' (are you missing an assembly reference?)

Source Error:
Line 22:     using System.Web.WebPages; 
Line 23:     using System.Web.Mvc;      
Line 24:     using System.Web.Mvc.Ajax;  
Line 25:     using System.Web.Mvc.Html;  
Line 26:     using System.Web.Routing;

After some googling i found out that you had to change "Copy Local" to true but i saw that it was already set to true in my project. Even after a clean and a rebuild this error persists.

So does anyone have an idea about what could cause this error?

Answer

Ross Bush picture Ross Bush · Nov 7, 2014

I think you are referencing an older version of System.Web. Right-click the project in vs and select 'Manage NuGet Packages' then search for Asp.Net MVC and click install. This will install the proper System.Web with Ajax. You can remove the six other binaries downloaded if they are not needed.

Related questions

Unobtrusive AJAX error: "Uncaught ReferenceError: Sys is not defined"

Example code: In an MVC 5 project in Visual Studio, I have set up the following controller and views: Controller TestController.cs public class TestController : BaseController { public ActionResult Index() { return View("Index"); } public PartialViewResult MyPartialView1() { return PartialView("PartialView1"); } public PartialViewResult MyPartialView2() { …

Read More
Send JSON data via POST (ajax) and receive json response from Controller (MVC)

I created a function in javascript like that: function addNewManufacturer() { var name = $("#id-manuf-name").val(); var address = $("#id-manuf-address").val(); var phone = $("#id-manuf-phone").val(); var sendInfo = { Name: name, Address: address, Phone: phone }; $.ajax({ type: "POST", url: "/Home/Add", dataType: "json", success: function (…

Read More
ASP.NET MVC controller actions that return JSON or partial html

I am trying to create controller actions which will return either JSON or partial html depending upon a parameter. What is the best way to get the result returned to an MVC page asynchronously?

Read More