ASP.Net MVC：如何读取我的自定义声明值

请参阅下面的代码。我知道通过这种方式我们可以将自定义数据添加到索赔中，但现在的问题是如何读回这些值。假设我想读回索赔价值电子邮件和电子邮件2请告诉我需要编写什么代码来读回索赔值电子邮件和电子邮件2.

UserManager<applicationuser> userManager = new UserManager<applicationuser>(new UserStore<applicationuser>(new SecurityContext()));
ClaimsIdentity identity = userManager.CreateIdentity(user, DefaultAuthenticationTypes.ApplicationCookie
var user = userManager.Find(userName, password);
identity.AddClaim(new Claim("Email", user.Email));
identity.AddClaim(new Claim("Email2", user.Email));

你可以使用FindFirst(string type)方法上ClaimsIdentity根据索赔类型检索索赔。在这种情况下Email or Email2

var claimType = "Email";
var claim = identity.FindFirst(claimType);
var email = claim == null ? string.Empty : claim.Value;

我通常会将声明类型存储在常量中

public static partial class Constants {
    public class Security {
        public static class ClaimTypes {
            public const string Email = "http://schemas.mycompany.com/identity/claims/email";
            public const string Email2 = "http://schemas.mycompany.com/identity/claims/email2";
        }
    }
}

然后创建扩展方法以从IIdentity实施前提是它源自ClaimsIdentity.

public static class GenericIdentityExtensions {
    /// <summary>
    /// Return the Email claim
    /// </summary>
    public static string GetEmail(this IIdentity identity) {
        if (identity != null && identity.IsAuthenticated) {
            ClaimsIdentity claimsIdentity = identity as ClaimsIdentity;
            if (claimsIdentity != null)
                return claimsIdentity.FindFirstOrEmpty(Constants.Security.ClaimTypes.Email);
        }
        return string.Empty;
    }
    /// <summary>
    /// Return the Email2 claim
    /// </summary>
    public static string GetEmail2(this IIdentity identity) {
        if (identity != null && identity.IsAuthenticated) {
            ClaimsIdentity claimsIdentity = identity as ClaimsIdentity;
            if (claimsIdentity != null)
                return claimsIdentity.FindFirstOrEmpty(Constants.Security.ClaimTypes.Email2);
        }
        return string.Empty;
    }
    /// <summary>
    /// Retrieves the first claim that is matched by the specified type if it exists, String.Empty otherwise.
    /// </summary>
    internal static string FindFirstOrEmpty(this ClaimsIdentity identity, string claimType) {
        var claim = identity.FindFirst(claimType);
        return claim == null ? string.Empty : claim.Value;
    }
}