public class Home1Controller : Controller
{
  //匿名访问
  public ActionResult Index()
  {
    return View();
  }
  //登录用户访问
  [RequestAuthorize]
  public ActionResult Index2()
  {
    return View();
  }
  //登录用户，张三才能访问
  [RequestAuthorize(Users="张三")]
  public ActionResult Index3()
  {
    return View();
  }
  //管理员访问
  [RequestAuthorize(Roles="Admin")]
  public ActionResult Index4()
  {
    return View();
  }
}

//Controller级别的权限控制
[RequestAuthorize(User="张三")]
public class Home2Controller : Controller
{
  //登录用户访问
  public ActionResult Index()
  {
    return View();
  }
  //允许匿名访问
  [AllowAnonymous]
  public ActionResult Index2()
  {
    return View();
  }
}

<?xml version="1.0" encoding="utf-8" ?>
<!--
  1.这里可以把权限控制转移到配置文件，这样就不用在程序中写roles和users了
  2.如果程序也写了，那么将覆盖配置文件的。
  3.action级别的优先级 > controller级别 > Area级别  
-->
<root>
 <!--area级别-->
 <area name="Admin">
  <roles>Admin</roles>
 </area>
  
 <!--controller级别-->
 <controller name="Home2">
  <user>张三</user>
 </controller>
  
 <!--action级别-->
 <controller name="Home1">
  <action name="Inde3">
   <users>张三</users>
  </action>
  <action name="Index4">
   <roles>Admin</roles>
  </action>
 </controller>
</root>

public interface IPrincipal
{
  //标识对象
  IIdentity Identity { get; }
  //判断当前角色是否属于指定的角色
  bool IsInRole(string role);
}

public interface IIdentity
{  
  //身份验证类型
  string AuthenticationType { get; }
  //是否验证通过
  bool IsAuthenticated { get; } 
  //用户名
  string Name { get; }
}

public class UserData : IUserData
{
  public long UserID { get; set; }
  public string UserName { get; set; }
  public string UserRole { get; set; }
 
  public bool IsInRole(string role)
  {
    if (string.IsNullOrEmpty(role))
    {
      return true;
    }
    return role.Split(',').Any(item => item.Equals(this.UserRole, StringComparison.OrdinalIgnoreCase));      
  }
 
  public bool IsInUser(string user)
  {
    if (string.IsNullOrEmpty(user))
    {
      return true;
    }
    return user.Split(',').Any(item => item.Equals(this.UserName, StringComparison.OrdinalIgnoreCase));
  }
}

public interface IUserData
{
  bool IsInRole(string role);
  bool IsInUser(string user);
}
　　接下来定义一个Principal实现IPrincipal接口，如下：
public class Principal : IPrincipal    
{
  public IIdentity Identity{get;private set;}
  public IUserData UserData{get;set;}
 
  public Principal(FormsAuthenticationTicket ticket, IUserData userData)
  {
    EnsureHelper.EnsureNotNull(ticket, "ticket");
    EnsureHelper.EnsureNotNull(userData, "userData");
    this.Identity = new FormsIdentity(ticket);
    this.UserData = userData;
  }
 
  public bool IsInRole(string role)
  {
    return this.UserData.IsInRole(role);      
  }   
 
  public bool IsInUser(string user)
  {
    return this.UserData.IsInUser(user);
  }
}

public class HttpFormsAuthentication
{    
  public static void SetAuthenticationCookie(string userName, IUserData userData, double rememberDays = 0)            
  {
    EnsureHelper.EnsureNotNullOrEmpty(userName, "userName");
    EnsureHelper.EnsureNotNull(userData, "userData");
    EnsureHelper.EnsureRange(rememberDays, "rememberDays", 0);
 
    //保存在cookie中的信息
    string userJson = JsonConvert.SerializeObject(userData);
 
    //创建用户票据
    double tickekDays = rememberDays == 0 ? 7 : rememberDays;
    var ticket = new FormsAuthenticationTicket(2, userName,
      DateTime.Now, DateTime.Now.AddDays(tickekDays), false, userJson);
 
    //FormsAuthentication提供web forms身份验证服务
    //加密
    string encryptValue = FormsAuthentication.Encrypt(ticket);
 
    //创建cookie
    HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptValue);
    cookie.HttpOnly = true;
    cookie.Domain = FormsAuthentication.CookieDomain;
 
    if (rememberDays > 0)
    {
      cookie.Expires = DateTime.Now.AddDays(rememberDays);
    }      
    HttpContext.Current.Response.Cookies.Remove(cookie.Name);
    HttpContext.Current.Response.Cookies.Add(cookie);
  }
 
  public static Principal TryParsePrincipal<TUserData>(HttpContext context)              
    where TUserData : IUserData
  {
    EnsureHelper.EnsureNotNull(context, "context");
 
    HttpRequest request = context.Request;
    HttpCookie cookie = request.Cookies[FormsAuthentication.FormsCookieName];
    if(cookie == null || string.IsNullOrEmpty(cookie.Value))
    {
      return null;
    }
    //解密cookie值
    FormsAuthenticationTicket ticket = FormsAuthentication.Decrypt(cookie.Value);
    if(ticket == null || string.IsNullOrEmpty(ticket.UserData))          
    {
      return null;            
    }
    IUserData userData = JsonConvert.DeserializeObject<TUserData>(ticket.UserData);       
    return new Principal(ticket, userData);
  }
}

public ActionResult Login(string userName,string password)
{
  //验证用户名和密码等一些逻辑... 
 
  UserData userData = new UserData()
  {
    UserName = userName,
    UserID = userID,
    UserRole = "Admin"
  };
  HttpFormsAuthentication.SetAuthenticationCookie(userName, userData, 7);
   
  //验证通过...
}

protected void Application_AuthenticateRequest(object sender, EventArgs e)
{
  HttpContext.Current.User = HttpFormsAuthentication.TryParsePrincipal<UserData>(HttpContext.Current);
}

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class RequestAuthorizeAttribute : AuthorizeAttribute
{
  //验证
  public override void OnAuthorization(AuthorizationContext context)
  {
    EnsureHelper.EnsureNotNull(context, "httpContent");      
    //是否允许匿名访问
    if (context.ActionDescriptor.IsDefined(typeof(AllowAnonymousAttribute), false))
    {
      return;
    }
    //登录验证
    Principal principal = context.HttpContext.User as Principal;
    if (principal == null)
    {
      SetUnAuthorizedResult(context);
      HandleUnauthorizedRequest(context);
      return;
    }
    //权限验证
    if (!principal.IsInRole(base.Roles) || !principal.IsInUser(base.Users))
    {
      SetUnAuthorizedResult(context);
      HandleUnauthorizedRequest(context);
      return;
    }
    //验证配置文件
    if(!ValidateAuthorizeConfig(principal, context))
    {
      SetUnAuthorizedResult(context);
      HandleUnauthorizedRequest(context);
      return;
    }      
  }
 
  //验证不通过时
  private void SetUnAuthorizedResult(AuthorizationContext context)
  {
    HttpRequestBase request = context.HttpContext.Request;
    if (request.IsAjaxRequest())
    {
      //处理ajax请求
      string result = JsonConvert.SerializeObject(JsonModel.Error(403));        
      context.Result = new ContentResult() { Content = result };
    }
    else
    {
      //跳转到登录页面
      string loginUrl = FormsAuthentication.LoginUrl + "?ReturnUrl=" + preUrl;
      context.Result = new RedirectResult(loginUrl);
    }
  }
 
　　//override
  protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
  {
    if(filterContext.Result != null)
    {
      return;
    }
    base.HandleUnauthorizedRequest(filterContext);
  }
}

  private bool ValidateAuthorizeConfig(Principal principal, AuthorizationContext context)
  {
    //action可能有重载，重载时应该标记ActionName区分
    ActionNameAttribute actionNameAttr = context.ActionDescriptor
      .GetCustomAttributes(typeof(ActionNameAttribute), false)
      .OfType<ActionNameAttribute>().FirstOrDefault();
    string actionName = actionNameAttr == null ? null : actionNameAttr.Name;
    AuthorizationConfig ac = ParseAuthorizeConfig(actionName, context.RouteData);
    if (ac != null)
    {
      if (!principal.IsInRole(ac.Roles))
      {
        return false;
      }
      if (!principal.IsInUser(ac.Users))
      {
        return false;
      }
    }
    return true;
  }
 
  private AuthorizationConfig ParseAuthorizeConfig(string actionName, RouteData routeData)
  {
    string areaName = routeData.DataTokens["area"] as string;
    string controllerName = null;
    object controller, action;
    if(string.IsNullOrEmpty(actionName))
    {
      if(routeData.Values.TryGetValue("action", out action))
      {
        actionName = action.ToString();
      }
    }
    if (routeData.Values.TryGetValue("controller", out controller))
    {
      controllerName = controller.ToString();
    }
    if(!string.IsNullOrEmpty(controllerName) && !string.IsNullOrEmpty(actionName))
    {
      return AuthorizationConfig.ParseAuthorizationConfig(
        areaName, controllerName, actionName);
    }
    return null;
  }
}

public class AuthorizationConfig
{
  public string Roles { get; set; }
  public string Users { get; set; }
 
  private static XDocument _doc;
 
  //配置文件路径
  private static string _path = "~/Identity/Authorization.xml";
 
  //首次使用加载配置文件
  static AuthorizationConfig()
  {
    string absPath = HttpContext.Current.Server.MapPath(_path);
    if (File.Exists(absPath))
    {
      _doc = XDocument.Load(absPath);
    }
  }
 
  //解析配置文件，获得包含Roles和Users的信息
  public static AuthorizationConfig ParseAuthorizationConfig(string areaName, string controllerName, string actionName)
  {
    EnsureHelper.EnsureNotNullOrEmpty(controllerName, "controllerName");
    EnsureHelper.EnsureNotNullOrEmpty(actionName, "actionName");
 
    if (_doc == null)
    {
      return null;
    }
    XElement rootElement = _doc.Element("root");
    if (rootElement == null)
    {
      return null;
    }
    AuthorizationConfig info = new AuthorizationConfig();
    XElement rolesElement = null;
    XElement usersElement = null;
    XElement areaElement = rootElement.Elements("area")
      .Where(e => CompareName(e, areaName)).FirstOrDefault();
    XElement targetElement = areaElement ?? rootElement;
    XElement controllerElement = targetElement.Elements("controller")
      .Where(e => CompareName(e, controllerName)).FirstOrDefault();
 
    //如果没有area节点和controller节点则返回null
    if (areaElement == null && controllerElement == null)
    {
      return null;
    }
    //此时获取标记的area
    if (controllerElement == null)
    {
      rootElement = areaElement.Element("roles");
      usersElement = areaElement.Element("users");
    }
    else
    {
      XElement actionElement = controllerElement.Elements("action")
        .Where(e => CompareName(e, actionName)).FirstOrDefault();
      if (actionElement != null)
      {
        //此时获取标记action的
        rolesElement = actionElement.Element("roles");
        usersElement = actionElement.Element("users");
      }
      else
      {
        //此时获取标记controller的
        rolesElement = controllerElement.Element("roles");
        usersElement = controllerElement.Element("users");
      }
    }
    info.Roles = rolesElement == null ? null : rolesElement.Value;
    info.Users = usersElement == null ? null : usersElement.Value;
    return info;
  }
 
  private static bool CompareName(XElement e, string value)
  {
    XAttribute attribute = e.Attribute("name");
    if (attribute == null || string.IsNullOrEmpty(attribute.Value))
    {
      return false;
    }
    return attribute.Value.Equals(value, StringComparison.OrdinalIgnoreCase);
  }
}