我正在构建一个WebAPI，我的模型中有一些元数据列，比如InsertUser和UpdateUser。我正在使用Microsoft.Identity对用户进行身份验证

services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
  .AddMicrosoftIdentityWebApi(_configuration.GetSection("AzureAd"))
  .EnableTokenAcquisitionToCallDownstreamApi()
  .AddMicrosoftGraph(_configuration.GetSection("MicrosoftGraph"))
  .AddInMemoryTokenCaches();

我想在成功验证后调用Graph，并将DisplayName存储在某个地方，以便在SaveChanges中的DataContext中使用它。如何才能做到这一点？

• • DataContext. cs**

public override int SaveChanges()
{
    var entries = ChangeTracker
        .Entries()
        .Where(e => e.Entity is BaseEntity && (
                e.State == EntityState.Added
                || e.State == EntityState.Modified));

    foreach (var entityEntry in entries)
    {
        ((BaseEntity)entityEntry.Entity).UpdateTimestamp = DateTime.UtcNow;
        ((BaseEntity)entityEntry.Entity).UpdateUser = "System"; //Change to logged in user

        if (entityEntry.State == EntityState.Added)
        {
            ((BaseEntity)entityEntry.Entity).InsertTimestamp = DateTime.UtcNow;
            ((BaseEntity)entityEntry.Entity).InsertUser = "System"; //Change to logged in user
        }
    }

    return base.SaveChanges();
}

我试着遵循一些教程，并尝试将其存储到ClaimsIdentity中

• • Startup. cs**

services.Configure<JwtBearerOptions>(JwtBearerDefaults.AuthenticationScheme, options =>
{
    options.Events ??= new JwtBearerEvents
    {
        OnTokenValidated = async context =>
        {
            var userProfileService = context.HttpContext.RequestServices.GetRequiredService<IUserProfile>();
            var user = await userProfileService.RetrieveUserProfileAsync();

            var identity = context.Principal.Identity as ClaimsIdentity;
            if (identity != null)
            {
                identity.AddClaim(new Claim("DisplayName", user.DisplayName));
            }
        }
    };
});
services.AddScoped<IUserProfile, UserProfile>();

• • UserProfile. cs**

using Microsoft.Graph;

namespace WebAPI.Services
{
    public interface IUserProfile
    {
        Task<User> RetrieveUserProfileAsync();
    }
    public class UserProfile : IUserProfile
    {
        private readonly GraphServiceClient _graphServiceClient;

        public UserProfile(GraphServiceClient graphServiceClient)
        {
            _graphServiceClient = graphServiceClient;
        }

        public async Task<User> RetrieveUserProfileAsync()
        {
            var user = await _graphServiceClient.Me.Request().GetAsync();
            return user;
        }
    }
}

为了测试，我在进行api调用时添加了这个

var claimsIdentity = _httpContextAccessor.HttpContext?.User?.Identity as ClaimsIdentity;
var userProfileDisplayName = claimsIdentity?.FindFirst("DisplayName")?.Value;
Console.WriteLine($"User: {userProfileDisplayName}");

但它只打印User:。我做错了什么，我该如何修复它？