在WebApi 中使用AutoFac

參考文檔

https://www.cnblogs.com/htsboke/p/10956807.html

https://www.cnblogs.com/lenmom/p/8510572.html

在WebApi項目中使用AutoFac，結構如下：

首先在Api項目當中引用AutoFac包，如下圖所示：

倉儲類：

 1     public interface IUsersRepository
 2     {
 3         int GetUserIsExists(UsersEntity criteria);
 4 
 5     }
 6 
 7 
 8     public class UsersRepository : IUsersRepository
 9     {
10         Logger log = LogManager.GetLogger("UsersRepository");
11 
12         /// <summary>
13         /// 獲取用戶是否存在
14         /// </summary>
15         /// <param name="criteria"></param>
16         /// <returns></returns>
17         public int GetUserIsExists(UsersEntity criteria)
18         {
19             string sql = "。。。。";
20             try
21             {
22                  //查詢sql代碼，此處省略。。。。             
               }
28             catch (Exception ex)
29             {
30                 log.Fatal(ex, "獲取用戶是否存在異常：{0}，SQL：{1}", ex.Message, sql);
31                 return 0;
32             }
33         }
34     }

服務類：

 1     //介面   
       public interface IUsersService
 4     {
 5         int GetUserIsExists(UsersEntity criteria);
 6 
 7     }
 8 
10     //實現類
11     public class UsersService : IUsersService
12     {
13         private readonly IUsersRepository _usersrepository;     
14         public UsersService(IUsersRepository usersrepository)    //通過構造函數註入
15         {
16             _usersrepository = usersrepository;
17         }
18 
19         /// <summary>
20         /// 獲取用戶是否存在
21         /// </summary>
22         /// <param name="criteria"></param>
23         /// <returns></returns>
24         public int GetUserIsExists(UsersEntity criteria)
25         {
26             return _usersrepository.GetUserIsExists(criteria);
27         }
28     }

在Api介面項目中創建一個AutoFac工具類：AutofacUtil.cs   

 1     public class AutofacUtil
 2     {
 3         private static IContainer _container;
 4 
 5         public static void ConfigureContainer()
 6         {
 7             #region AutoFac IOC容器
 8 
 9             var builder = new ContainerBuilder();
10 
11             try
12             {
13                 //builder.RegisterControllers(Assembly.GetCallingAssembly());  //註冊mvc控制器  需要引用package Autofac.Mvc
14 
15                 //builder.RegisterApiControllers(Assembly.GetExecutingAssembly()).PropertiesAutowired();  //支持Api控制器屬性註入
16                 builder.RegisterApiControllers(Assembly.GetCallingAssembly());  //註冊所有api控制器  構造函數註入  需要引用package Autofac.WebApi
17 
18                 //註冊程式集
19                 #region Service
20                 var assemblysServices = Assembly.Load("WebApi.Service");
21                 builder.RegisterAssemblyTypes(assemblysServices)
22                 .AsImplementedInterfaces()
23                 .InstancePerDependency();
24                 #endregion
25                 
26                 #region Repository
27                 var assemblysRepository = Assembly.Load("WebApi.Repository");
28                 builder.RegisterAssemblyTypes(assemblysRepository)
29                 .AsImplementedInterfaces()
30                 .InstancePerDependency();
31                 #endregion
32 
33                 _container = builder.Build();   //創建依賴註入
34 
35 
36                 //設置MVC依賴註入
37                 //DependencyResolver.SetResolver(new AutofacDependencyResolver(_container));
38 
39                 //設置WebApi依賴註入
40                 GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver(_container);
41             }
42             catch (Exception ex)
43             {
44                 throw new Exception(ex.Message + "\n" + ex.InnerException);
45             }
46             #endregion
47         }
48 
49         /// <summary>
50         /// 從Autofac容器獲取對象
51         /// </summary>
52         /// <typeparam name="T"></typeparam>
53         /// <returns></returns>
54         public static T GetFromFac<T>()
55         {
56             return _container.Resolve<T>();
57         }
58 
59     }

在 Global.asax.cs 全局中註冊一下：

 1   public class WebApiApplication : System.Web.HttpApplication
 2     {
 3         protected void Application_Start()
 4         {
 5             AreaRegistration.RegisterAllAreas();
 6             GlobalConfiguration.Configure(WebApiConfig.Register);
 7             FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
 8             RouteConfig.RegisterRoutes(RouteTable.Routes);
 9             BundleConfig.RegisterBundles(BundleTable.Bundles);
10 
11             //AutoFac 註冊
12             AutofacUtil.ConfigureContainer();
13 
14         }
15     }

最後在介面中使用：

 1     public class UsersController : ApiController
 2     {
 3         private readonly IUsersService _usersService;
 4         public UsersController(IUsersService usersService)    //使用構造函數註入
 5         {
 6             _usersService = usersService;
 7         }
 8 
 9 
10         /// <summary>
11         /// 獲取用戶是否存在
12         /// </summary>
13         /// <param name="username"></param>
14         /// <param name="password"></param>
15         /// <returns></returns>
16         [HttpPost]
17         public IHttpActionResult GetUserIsExists(string username, string password)
18         {
19             //驗證是否存在當前用戶
20             var obModel = new UsersEntity()
21             {
22                 Username = username,
23                 Password = Encryption.MD5(password)
24             };
25             var getresult = _usersService.GetUserIsExists(obModel);
26 
27             return Json(new { isexists = getresult > 0 });
28         }
29 
30 
31     }

測試結果：

最後：如果出現 未將對象引用的實例 的錯誤，檢查一下是否引用相應的dll程式集了。