HtmlHelper does not contain definition for "Action"

I use <%= Html.Action("ReadXML") %> and have this error:

'System.Web.Mvc.HtmlHelper' does not contain a definition for 'Action' and no extension method 'Action' accepting a first argument of type 'System.Web.Mvc.HtmlHelper' could be found (are you missing a using directive or an assembly reference?)

How fix it

This is my assemblies:

   <assemblies>
    <add assembly="System.Core, Version=3.5.0.0, Cult开发者_运维知识库ure=neutral, PublicKeyToken=B77A5C561934E089" />
    <add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <add assembly="System.Web.Abstractions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <add assembly="System.Web.Routing, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <add assembly="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <add assembly="System.Data.DataSetExtensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
    <add assembly="System.Xml.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
    <add assembly="System.Data.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
    <add assembly="System.Data.Entity, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />

  </assemblies>

Action is an extension method contained in the System.Web.Mvc assembly. Make sure you have referenced the following namespaces in your web.config:

<pages>
  <namespaces>
    <add namespace="System.Web.Mvc" />
    <add namespace="System.Web.Mvc.Ajax" />
    <add namespace="System.Web.Mvc.Html" />
    <add namespace="System.Web.Routing" />
  </namespaces>
</pages>

The method is declared in the System.Web.Mvc.Html namespace.

Also make sure your project is ASP.NET MVC 2.0 as this method has been added in the 2.0 version.

Make sure there is a reference to System.Web.Mvc in your project (add it if not already there).

Then make sure the class that is displaying this problem is importing the namespace - you can do this in a couple of ways:

• In the code behind add a using System.Web.Mvc; statement at the top.
• You can also import the namespace directly in the aspx page if needed, by using this statement: <%@ import namespace="System.Web.Mvc"%>

If you want to get the url to an action method inside i.e. a controller you can do:

var baseUrl = "http://localhost:12345";
var urlHelper = new UrlHelper(HttpContext.Current.Request.RequestContext);
var resource = urlHelper.Action("Home", "Index");
var uri = new Uri($"{baseUrl}{resource}");
Console.WriteLine(uri.ToString()); // ==> http://localhost:12345/Home/Index