我正在尝试编写一个简单的Web api项目,其中包含每秒执行一次方法的后台服务。此方法遍历列表,仅打印(暂时)一些统计信息。我在后台服务的构造函数中声明了一个新列表。
我目前在从控制器内部添加和删除项目时遇到一些问题。
public UsersController(IUserBackgroundService userService)
{
private readonly IUserBackgroundService _userService;
public UserController(IUserBackgroundService userService)
{
_userService = userservice;
}
[HttpPost]
public IActionResult PostUser(User user)
{
_userService.Add(user)
}
}
public UserService: BackgroundService, IUserService
{
private List<User> Users;
public UserService()
{
Users = new List<Users>();
}
protected override ExecuteAsync(CancellationToken token)
{
//this will execute the GenerateUserStats every second
}
//this method is being executed every second
protected Task GenerateUserStatistics()
{
Console.WriteLine($"Nr. of users {users.count}");
foreach(var user in users)
{
Console.WriteLine($"{user.fname} {user.sname}");
}
}
//add a user to the collection
// this is called by the PostUser method of my controller.
public void AddUser(User user)
{
Users.Add(user);
}
public void RemoveUser(string id)
{
var user = Users.FirstOrDefault(u => u.Id == id);
Users.Remove(user);
}
}
我希望每次我调用PostUser()时,Users列表都会增加,而我的GenerateStatistics()方法应打印出正确的值,而打印出的只是Nr个用户0。
我将该服务注册为托管服务和单例。我暂时不在代码中省略了一些内容,因为我在这台机器上没有代码。
将您的backgroundService注册为Startup.cs的IHostedService
中的ConfigureServices
,如下所示:
services.AddSingleton<UserService>();
services.AddSingleton<IHostedService, UserService>(
serviceProvider => serviceProvider.GetService<UserService>());
然后在控制器中注入依赖项服务:
public class UsersController : ControllerBase
{
private readonly UserService _userService;
public UsersController(UserService userService)
{
_userService = userService;
}
[HttpPost]
public IActionResult PostUser(User user)
{
_userService.AddUser(user);
return Ok();
}
}
参考:https://github.com/simpleinjector/SimpleInjector/issues/596