问在ASP.NET核心中放置公共变量的位置

EN

//In your ConfigureServices method , add your services that will be injected whenever view component is instantiated
public void ConfigureServices(IServiceCollection services) {
   services.AddSingleton<IUserRespository, UserRepository>();
}

//Now Create a view component 
public class LoggedInUser : ViewComponent
{        
    private IUserRespository userRepository;

  //Services can be injected using asp.net core DI container
    public LoggedInUser(IUserRepository userRepository,SomeOtherService service)
    {
       //assign services to local variable for use later
       this.userRepository = userRepository;
    }

    //This method can take any number of parameters and returns view
    public async Task<IViewComponentResult> InvokeAsync(int param1,string param2,etc    )
    {
       //get the logged in user data here using available services
       var loggedInUserData = GetSomeData(context);
        return View(loggedInUserData );
    }

}

@model LoggedInUserModel
<div>
 <!-- html here to render model -->
</div>

@await Component.InvokeAsync("LoggedInUser", new { param1=value,param2=value,etc })

var mockRepository = Mock of ICityRepository;
var viewComponent= new LoggedInUser(mockRepository);
ViewViewComponentResult result
= viewComponent.Invoke() as ViewViewComponentResult; //using Invoke here instead of InvokeAsnyc for simplicity
//Add your assertions now on result