MudBlazor与ASP.NET Core UserManager并行执行DbContext跟踪冲突问题

场景复现 #

• 应用右上角设有个人资料下拉菜单，点击“编辑资料”跳转至对应页面时，两个组件会同时加载
• 刷新页面时，MudBlazor会并行加载这两个组件，两者均在OnInitializedAsync方法内通过ASP.NET Core的UserManager获取当前用户

核心问题 #

两个UserManager请求复用了同一个DbContext，导致抛出ApplicationUser实例已被跟踪的错误。疑惑：UserManager作为作用域服务，默认情况下难道不具备线程安全性吗？

已实现的解决方案 #

通过自定义UserService结合TaskCompletionSource处理并行请求，确保只执行一次用户查询，代码如下：

public class UserService(SignInManager<ApplicationUser> signInManager, IHttpContextAccessor httpContextAccessor)
    : IUserService
{
    public SignInManager<ApplicationUser> SignInManager { get; } = signInManager;

    private readonly TaskCompletionSource<ApplicationUser?> _taskCompletionSource = new();

    private int _isInitialized = 0;

    public async Task<ApplicationUser?> GetUserAsync(ClaimsPrincipal claimsPrincipal)
    {
        if (Interlocked.CompareExchange(ref _isInitialized, 1, 0) == 0)
        {
            var user = await SignInManager.UserManager.GetUserAsync(claimsPrincipal);
            _taskCompletionSource.SetResult(user);
            return user;
        }
        return await _taskCompletionSource.Task;
    }

    public async Task<ApplicationUser?> GetUserAsync()
    {
        var user = httpContextAccessor.HttpContext?.User;
        if (user != null)
        {
            return await GetUserAsync(user);
        }
        return null;
    }
}

在Program.cs中的注册方式：

services.AddScoped<IUserService, UserService>();

希望了解是否存在官方或更简洁的默认线程安全实现方式。

内容的提问来源于stack exchange，提问作者CrazyEight