您使用ASP.NET MVC 4的网络模板？如果不是，我建议你创建网络模板创建一个新的ASP.NET MVC项目，打开账户控制器，有一个外观和方法。

作为@ USER1正确地说，你可以做到这一点是使用的方法之一

  FormsAuthentication.SetAuthCookie（用户名，真实）;
 返回重定向（RETURNURL）;
 

但正如你说，你正在使用ASP.NET MVC 4，您应该使用WebSecurity类。

例如：

  WebSecurity.Login（model.UserName，model.Password）;
返回RedirectToAction（指数，家）;
 

大部分的工作是使用WebSecurity帮手以下方法和属性来完成：

• WebSecurty.UserExists, WebSecurity.CreateUserAndAccount.这些方法让你判断一个人是否已经注册和注册。




• WebSecurty.IsAuthenticated.此属性允许您确定当前用户是否登录，这是有用的，如果他们没有在已经登录的用户重定向到登录页面。




• WebSecurity.Login, WebSecurity.Logout.这些方法或退出登录用户。




• WebSecurity.CurrentUserName.此属性是有用的显示当前用户的登录名（如果用户登录）。




• WebSecurity.ConfirmAccount.如果设置了注册确认电子邮件此方法非常有用。 （详情载于博客文章使用了ASP.NET网页安全确认的功能描述。）

延伸阅读：

• 添加安全和成员到ASP.NET网页（剃刀）网站


• WebSecurity VS在ASP.NET MVC4
FormsAuthentication

Here are some bits of code from my attempt. It does not work; after "logging in", the user isn't redirected to the home/index page, but the login page just reloads.

Web.config:

<authentication mode="Forms">
  <forms loginUrl="~/Account/Login" />
</authentication>

...

<defaultDocument>
  <files>
    <add value="~/Account/Login"/>
  </files>
</defaultDocument>

Controllers/AccountController.cs:

public class AccountController : Controller
{
    //
    // GET: /Account/Login
    public ActionResult Login()
    {
        return View();
    }
}

Views/Account/Login.aspx:

<asp:Login ID="login" runat="server" DestinationPageUrl="~/Views/Home/Index.aspx">
    ...
</asp:Login>

Are you using the internet template of ASP.NET MVC 4 ? if not I suggest you create a new ASP.NET MVC project with internet template, open the Account Controller and have a look and the methods.

As @user1 has rightly said one of the way you could do this is using

 FormsAuthentication.SetAuthCookie(username, true);
 return Redirect(returnurl);

But as you say, you are using ASP.NET MVC 4. You should use WebSecurity Class.

For example :

WebSecurity.Login(model.UserName, model.Password);
return RedirectToAction("Index", "Home");

Most of the work is done using the following methods and properties of the WebSecurity helper:

• WebSecurty.UserExists, WebSecurity.CreateUserAndAccount. These methods let you determine whether someone is already registered and to register them.

• WebSecurty.IsAuthenticated. This property lets you determine whether the current user is logged in. This is useful to redirect users to a login page if they have not already logged in.

• WebSecurity.Login, WebSecurity.Logout. These methods log a user in or out.

• WebSecurity.CurrentUserName. This property is useful for displaying the current user's logged-in name (if the user is logged in).

• WebSecurity.ConfirmAccount. This method is useful if you set up email confirmation for registration. (Details are described in the blog post Using the confirmation feature for ASP.NET Web Pages security.)

Further Reading :

• Adding Security and Membership to an ASP.NET Web Pages (Razor) Site
• WebSecurity vs FormsAuthentication in ASP.NET MVC4