1. 首先,我们需要在 Startup.cs 文件中启用身份验证，并添加以下服务：

services.AddAuthentication(option => { option.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme; option.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme; }).AddJwtBearer(options => { options.SaveToken = true; options.RequireHttpsMetadata = false;
options.TokenValidationParameters = new TokenValidationParameters { ValidateIssuer = true, ValidateAudience = true, ValidateLifetime = true, ValidateIssuerSigningKey = true,
ValidIssuer = Configuration["Jwt:Issuer"], ValidAudience = Configuration["Jwt:Audience"], IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(Configuration["Jwt:SecretKey"])) }; });

2. 接下来，我们需要使用以下代码向 HttpContext 中添加用户：

public class UserContextMiddleware { private readonly RequestDelegate _next; private readonly UserManager _userManager;

public UserContextMiddleware(RequestDelegate next)
{
    _next = next;
}

public async Task InvokeAsync(HttpContext context, UserManager userManager)
{
    _userManager = userManager;

    if (context.User.Identity.IsAuthenticated)
    {
        var userName = context.User.Identity.Name;
        var user = await _userManager.FindByNameAsync(userName);

        if (user != null)
        {
            context.Items["User"] = user;
        }
    }

    await _next(context);
}

}

3. 然后，我们可以在 SaveChangesAsync 中获取当前用户并将其保存到我们的实体类中：

public class ApplicationDbContext : DbContext { private readonly IHttpContextAccessor httpContextAccessor;

public ApplicationDbContext(DbContextOptions options, IHttpContextAccessor httpContextAccessor)
    : base(options)
{
    this.httpContextAccessor = httpContextAccessor;
}

public override int SaveChanges()
{
    AddAuditInfo();
    return base.SaveChanges();
}

public override async Task SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
{
    AddAuditInfo();
    return await base.SaveChangesAsync(cancellationToken);
}

private void AddAuditInfo()
{
    var username = httpContextAccessor.HttpContext.Items["User"] !=