配置标识，以现有的项目也不是很难的事情。您必须安装一些的NuGet包，并做一些小的配置。

Configuring Identity to your existing project is not hard thing. You must install some NuGet package and do some small configuration.

首先，在包管理器控制台安装这些包的NuGet：

First install these NuGet packages in Package Manager Console:

PM> Install-Package Microsoft.AspNet.Identity.Owin 
PM> Install-Package Microsoft.AspNet.Identity.EntityFramework
PM> Install-Package Microsoft.Owin.Host.SystemWeb 

添加一个用户类，并且使用 IdentityUser 继承：

public class AppUser : IdentityUser
{
    //add your custom properties which have not included in IdentityUser before
    public string MyExtraProperty { get; set; }  
}

做同样的事情角色：

Do same thing for role:

public class AppRole : IdentityRole
{
    public AppRole() : base() { }
    public AppRole(string name) : base(name) { }
    // extra properties here 
}

您的DbContext 父窗体修改的DbContext 到 IdentityDbContext＆LT; APPUSER＆GT; 是这样的：

Change your DbContext parent form DbContext to IdentityDbContext<AppUser> like this:

public class MyDbContext : IdentityDbContext<AppUser>
{
    // Other part of codes still same 
    // You don't need to add AppUser and AppRole 
    // since automatically added by inheriting form IdentityDbContext<AppUser>
}

如果你使用相同的连接字符串并启用迁移EF创建必要的表给你。

If you use same connection string and enabled migration EF create necessary tables for you.

（可选），你可以多大程度上的UserManager 添加所需的配置和定制：

Optionally you could extent UserManager to add your desired configuration and customization:

public class AppUserManager : UserManager<AppUser>
{
    public AppUserManager(IUserStore<AppUser> store)
        : base(store)
    {
    }

    // this method is called by Owin therefore best place to configure your User Manager
    public static AppUserManager Create(
        IdentityFactoryOptions<AppUserManager> options, IOwinContext context)
    {
        var manager = new AppUserManager(
            new UserStore<AppUser>(context.Get<MyDbContext>()));

        // optionally configure your manager
        // ...

        return manager;
    }
}

由于身份是基于OWIN需要配置OWIN太：

Since Identity is based on OWIN you need configure OWIN too:

一类加入 App_Start 文件夹（或其他任何地方，如果你想）。这个类由OWIN

Add a class to App_Start folder (or anywhere else if you want). This class is used by OWIN

namespace MyAppNamespace
{
    public class IdentityConfig
    {
        public void Configuration(IAppBuilder app)
        {
            app.CreatePerOwinContext(() => new MyDbContext());
            app.CreatePerOwinContext<AppUserManager>(AppUserManager.Create);
            app.CreatePerOwinContext<RoleManager<AppRole>>((options, context) =>
                new RoleManager<AppRole>(
                    new RoleStore<AppRole>(context.Get<MyDbContext>())));

            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                LoginPath = new PathString("/Home/Login"),
            });
        }
    }
}

几乎刚做这行code添加到您的的web.config 文件，以便OWIN可以找到你的启动类。

Almost done just add this line of code to your web.config file so OWIN could find your startup class.

<appSettings>
    <!-- other setting here -->
    <add key="owin:AppStartup" value="MyAppNamespace.IdentityConfig" />
</appSettings>

现在在整个项目中，你可以使用Identity就像新的项目已经通过安装VS.例如，考虑登陆行动

Now in entire project you could use Identity just like new project had already installed by VS. Consider login action for example

[HttpPost]
public ActionResult Login(LoginViewModel login)
{
    if (ModelState.IsValid)
    {
        var userManager = HttpContext.GetOwinContext().GetUserManager<AppUserManager>();
        var authManager = HttpContext.GetOwinContext().Authentication;

        AppUser user = userManager.Find(login.UserName, login.Password);
        if (user != null)
        {
            var ident = userManager.CreateIdentity(user, 
                DefaultAuthenticationTypes.ApplicationCookie);
            AuthManager.SignIn(
                new AuthenticationProperties { IsPersistent = false }, ident);
            return Redirect(login.ReturnUrl ?? Url.Action("Index", "Home"));
        }
    }
    ModelState.AddModelError("", "Invalid username or password");
    return View(login);
}

您可以使角色和添加到您的用户：

You could make roles and add to your users:

public ActionResult CreateRole(string roleName)
{
    var roleManager=HttpContext.GetOwinContext().GetUserManager<RoleManager<AppRole>>();

    if (!roleManager.RoleExists(roleName))
        roleManager.Create(new AppRole(roleName));
    // rest of code
} 

您可以添加任何作用，这样任何用户：

You could add any role to any user like this:

UserManager.AddToRole(UserManager.FindByName("username").Id, "roleName");

通过使用授权，你可以保护你的动作和控制器：

By using Authorize you could guard your actions or controllers:

[Authorize]
public ActionResult MySecretAction() {}

或

[Authorize(Roles = "Admin")]]
public ActionResult MySecretAction() {}

另外，你可以安装额外的包，并将其配置，以满足像 Microsoft.Owin.Security.Facebook 或任何你想你的要求。

Also you could install additional package and configure them to meet your requirement like Microsoft.Owin.Security.Facebook or whichever you want.

注意：不要忘记添加相关的命名空间到您的文件：

Note: Don't forget add relevant namespaces to your files:

using Microsoft.AspNet.Identity;
using Microsoft.Owin.Security;
using Microsoft.AspNet.Identity.Owin;
using Microsoft.AspNet.Identity.EntityFramework;
using Microsoft.Owin;
using Microsoft.Owin.Security.Cookies;
using Owin;

您还可以看到我其他的答案像this和this对于高级用途身份。

You could also see my other answers like this and this for advanced use of Identity.