在ASP NET CORE 3.0中，我们可以使用UserManager服务来获取当前登录用户的ID。以下是示例代码：

• 在Startup.cs中注册UserManager服务：

// Startup.cs using Microsoft.AspNetCore.Identity; //... public void ConfigureServices(IServiceCollection services) { //... services.AddIdentity() .AddEntityFrameworkStores() .AddDefaultTokenProviders(); //... }

• 在Controller或View中获取用户ID：

// Controller using Microsoft.AspNetCore.Identity; //... public class MyController : Controller { private readonly UserManager _userManager; public MyController(UserManager userManager) { _userManager = userManager; } public async Task Index() { // Get current logged in user ID var user = await _userManager.GetUserAsync(User); var userId = user?.Id;

    //...
}

}

// View @using Microsoft.AspNetCore.Identity @inject UserManager UserManager @{ var user = await UserManager.GetUserAsync(User); var userId = user?.Id; }