.NET学习笔记之默认依赖注入_实用技巧_

 services.AddSingleton

 services.AddScoped

 services.AddTransient

 /// 
 /// 用户接口 /// 
 public interface IUserService { string GetName(); } /// 
 /// 用户实现 /// 
 public class UserService : IUserService { public string GetName() { return "AZRNG"; } } 

 private readonly IUserService _userService; public UserController(IUserService userService) { _userService = userService; } [HttpGet] public ActionResult GetName() { return Ok(_userService.GetName()); } FromServices操作注入 [HttpGet] public ActionResult GetName([FromServices] IUserService _userService) { return Ok(_userService.GetName()); } 

 public void ConfigureServices(IServiceCollection services) { //将服务生命期的范围限定为单个请求的生命期 services.AddTransient(); } 

 private readonly IUserService _userService; public HomeController(IUserService userService) { _userService = userService; } public IActionResult Index() { var info = _userService.GetInfo(); return View(); } 

 private readonly IServiceProvider _service; public UserController(IServiceProvider service) { _service = service; } [HttpGet] public ActionResult GetName() { var _userService = (IUserService)_service.GetService(typeof(IUserService)); return Ok(_userService.GetName()); } 

 var provider = services.BuildServiceProvider(); var userserivce = provider.GetService(); //或 var userservice2 = provider.GetRequiredService();