在MVC中使用自定义成员和角色提供者实现IPrincipal和IIdentity

我坚持使用自定义iprincipal和iidentity对象的实现。我现在花了一天的时间来研究如何实现这些权利，并通过更多的信息来扩展它。

我想扩展信息@Context.User.Identity.Name与自定义变量，如全名或其他东西。

EDIT:现在我得到了以下代码，但如果我试图读取@((CustomPrincipal)Context.User.Identity).Nachname，我得到一个错误，System.Web.Security.FormsIdentity不能被转换为CustomPrincipal。

任何想法?

public class CustomPrincipal : GenericPrincipal
{
    public CustomPrincipal(IIdentity identity, String[] roles) : base(identity, roles){ 
    }
    public String Vorname { get; set; }
    public String Nachname { get; set; } 
}

AccountModel:

public class FormsAuthenticationService : IFormsAuthenticationService
{
    public void SignIn(string userName, bool createPersistentCookie)
    {
        if (String.IsNullOrEmpty(userName)) throw new ArgumentException("Der Wert darf nicht NULL oder leer sein.", "userName");
        // Grab user information to insert
        KIMembershipUser membershipUser = (KIMembershipUser)Membership.GetUser(userName);
        var customInfo = String.Format("{0}|{1}", membershipUser.Vorname, membershipUser.Nachname);
        // Create and encrypt the ticket
        var ticket = new FormsAuthenticationTicket(
            2, // Version number
            userName, // Username
            DateTime.Now, // Issue date
            DateTime.Now.AddMinutes(30), // Expiration date
            createPersistentCookie, // Is it persistent?
            customInfo // User data
        );
        var encTicket = FormsAuthentication.Encrypt(ticket);
        // Store the ticket into a cookie
        var cookie = FormsAuthentication.GetAuthCookie(FormsAuthentication.FormsCookieName,createPersistentCookie);
        cookie.Value = encTicket;
        // Append the cookie to the response
        HttpContext.Current.Response.Cookies.Add(cookie); 
        //FormsAuthentication.SetAuthCookie(userName, createPersistentCookie);
    }
    public void SignOut()
    {
        FormsAuthentication.SignOut();
    }
}

global.asax:

    protected void Application_PostAuthenticateRequest(){
        // Collect current security information
        var principal = HttpContext.Current.User as RolePrincipal;
        if (principal == null)
            return;
        var identity = principal.Identity as FormsIdentity;
        if (identity == null)
            return;
        var roles = principal.GetRoles();
        // Extract user data in the authentication ticket
        var customInfo = identity.Ticket.UserData;
        var tokens = customInfo.Split('|');
        // Build a richer principal object
        var CustomPrincipal = new CustomPrincipal(identity, roles){
            Vorname = tokens[0],
            Nachname = tokens[1]
        };
        // Store the new principal in the HttpContext
        HttpContext.Current.User = CustomPrincipal;
    }