owin身份验证中的当前用户

我开始为移动应用程序构建web api，但在实现身份验证方面遇到了困难。我使用Bearer，虽然一切都应该很好，但我无法从控制器中的操作中获取当前用户。HttpContext.Current.User.Identity.Name为null（这也是HttpContext.CCurrent.User.Intity.GetUserId（）的结果）

Startup.cs:

    public partial class Startup
    {
        public void Configuration(IAppBuilder app)
        {
            var config = new HttpConfiguration();
            ConfigureAuth(app);
            WebApiConfig.Register(config);
            app.UseWebApi(config);
        }
    }

Startup.Auth.cs

public partial class Startup
{
        static Startup()
        {
            OAuthOptions = new OAuthAuthorizationServerOptions
            {
                TokenEndpointPath = new PathString("/token"),
                Provider = new ApplicationOAuthProvider(),
                AccessTokenExpireTimeSpan = TimeSpan.FromDays(1),
                AllowInsecureHttp = true
            };
            OAuthBearerOptions = new OAuthBearerAuthenticationOptions();
        }
        public static OAuthAuthorizationServerOptions OAuthOptions { get; private set; }
        public static OAuthBearerAuthenticationOptions OAuthBearerOptions { get; private set; }

        public static string PublicClientId { get; private set; }
        public void ConfigureAuth(IAppBuilder app)
        {
            app.UseOAuthBearerAuthentication(new OAuthBearerAuthenticationOptions
            {
                AccessTokenProvider = new AuthenticationTokenProvider()
            });
            app.UseOAuthBearerTokens(OAuthOptions);
            app.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll);
        }
}

ApplicationOAuthProvider.cs:

        public override Task ValidateClientAuthentication(OAuthValidateClientAuthenticationContext context)
        {
            string clientId, clientSecret;
            if (!context.TryGetBasicCredentials(out clientId, out clientSecret))
            {
                return SetErrorAndReturn(context, "client error", "");
            }
            if (clientId == "secret" && clientSecret == "secret")
            {
                context.Validated();
                return Task.FromResult<object>(null);
            }
            return SetErrorAndReturn(context, "client error", "");
        }
        public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
        {
            context.OwinContext.Response.Headers.Add("Access-Control-Allow-Origin", new[] { "*" });
            using (AuthRepository _repo = new AuthRepository())
            {
                IdentityUser user = await _repo.FindUser(context.UserName, context.Password);
                if (user == null)
                {
                    context.SetError("invalid_grant", "The user name or password is incorrect.");
                    return;
                }
            }
            var identity = new ClaimsIdentity(context.Options.AuthenticationType);
            identity.AddClaim(new Claim("sub", context.UserName));
            identity.AddClaim(new Claim("role", "user"));
            context.Validated(identity);
        }

        public override Task TokenEndpoint(OAuthTokenEndpointContext context)
        {
            foreach (KeyValuePair<string, string> property in context.Properties.Dictionary)
            {
                context.AdditionalResponseParameters.Add(property.Key, property.Value);
            }
            return Task.FromResult<object>(null);
        }

AuthRepository.cs:

public class AuthRepository : IDisposable
    {
        private readonly AuthContext _ctx;
        private readonly UserManager<IdentityUser> _userManager;
        public AuthRepository()
        {
            _ctx = new AuthContext();
            _userManager = new UserManager<IdentityUser>(new UserStore<IdentityUser>(_ctx));
        }
        public async Task<IdentityResult> RegisterUser(UserModel userModel)
        {
            var user = new IdentityUser
            {
                UserName = userModel.UserName
            };
            var result = await _userManager.CreateAsync(user, userModel.Password);
            return result;
        }
        public async Task<IdentityUser> FindUser(string userName, string password)
        {
            IdentityUser user = await _userManager.FindAsync(userName, password);
            return user;
        }
        public void Dispose()
        {
            _ctx.Dispose();
            _userManager.Dispose();
        }
    }

AuthContext.cs:

public class AuthContext : IdentityDbContext<IdentityUser>
    {
        public AuthContext()
            : base("AuthContext")
        {
        }
    }

以及finnaly ValuesController.cs:

[Authorize]
public class ValuesController : ApiController
{
    public IEnumerable<string> Get()
    {
        return new String[] {HttpContext.Current.User.Identity.Name, HttpContext.Current.User.Identity.GetUserId(),ClaimsPrincipal.Current.Identity.Name};
    }
}

当我执行此操作时，我得到了3次null。尽管如此，整个身份验证过程似乎很好——只有当我发送了一个好的令牌时，我才能访问。有人知道这里出了什么问题吗？

identity.AddClaim(new Claim(ClaimTypes.Name, context.UserName));