Question

抱歉，我是IOC概念的新手。我一直在尝试在我的Web api项目中实现Unity.WebAPI（5.3.0。），但出现以下错误；

尝试创建类型为'TransactionController'的控制器时发生错误。确保控制器具有无参数的公共构造函数

UnityResolver类

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        var container = new UnityContainer();

        // register all your components with the container here
        // it is NOT necessary to register your controllers

        // e.g. container.RegisterType<ITestService, TestService>();

        container.RegisterType<IFService, FService>(new HierarchicalLifetimeManager());
        container.RegisterType<IMService, MService>(new HierarchicalLifetimeManager());
        container.RegisterType<ITransactionService, TransactionService>(new HierarchicalLifetimeManager());
        container.RegisterType<IMRepository, MRepository>();

        config.DependencyResolver = new UnityResolver(container);
    }
}

Web Api配置

 protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        GlobalConfiguration.Configure(WebApiConfig.Register);
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);
    }

Global.asax

    public class TransactionController : ApiController
{
    private readonly ITransactionService _transactionService;
    private readonly IMService _mService;

    /// <summary>
    /// Public constructor to initialize transaction service instance
    /// </summary>
    public TransactionController(ITransactionService transactiontService, IMService mService)
    {
        _mService = mService;
        _transactionService = transactiontService;
    }

    [HttpGet]
    public IHttpActionResult IsApiAlive()
    {

        return Ok();

    }

控制器

private readonly IMRepository _mRepository;      

public TransactionService(IMRepository mRepository)
    {
        _mRepository = mRepository;
    }

TransactionService类的构造函数

create or replace TRIGGER EXP_IMG AFTER INSERT OR UPDATE OF LAST_UPDATE
ON baeume 
for each row
    when (OLD.LAST_UPDATE != NEW.LAST_UPDATE OR NEW.LAST_UPDATE is not null)
declare
    PRAGMA AUTONOMOUS_TRANSACTION;      

BEGIN
        DECLARE               
        t_blob BLOB;
        t_len NUMBER;
        t_file_name VARCHAR2(1000);
        t_output UTL_FILE.FILE_TYPE;
        t_TotalSize NUMBER;
        t_position NUMBER := 1;
        t_chucklen NUMBER := 32767;
        t_chuck RAW(32767);
        t_remain NUMBER;

        BEGIN                                   
          FOR var_a IN
          (                                     
            SELECT GUID, last_update
            FROM baeume
            WHERE image IS NOT NULL
            ORDER BY guid
          )
          LOOP 

          BEGIN
          --t_blob BLOB;
          t_len := 0;
          t_file_name := '';
          --t_output UTL_FILE.FILE_TYPE;
          t_TotalSize := 0;
          t_position  := 1;
          t_chucklen  := 32767;
          --t_chuck := (4096);
          t_remain := 0; 

              SELECT DBMS_LOB.GETLENGTH (image), TO_CHAR (guid) || '.jpg'
              INTO t_TotalSize, t_file_name
              FROM baeume
              WHERE guid = var_a.guid;

              t_remain := t_TotalSize;
              t_output := UTL_FILE.FOPEN ('DIR_IMG', t_file_name, 'wb', 32760);

              SELECT image
              INTO t_blob 
              FROM baeume
              WHERE guid= var_a.guid;

              WHILE t_position < t_TotalSize
                LOOP
                DBMS_LOB.READ (t_blob, t_chucklen, t_position, t_chuck);
                UTL_FILE.PUT_RAW (t_output, t_chuck);
                UTL_FILE.FFLUSH (t_output);
                t_position := t_position + t_chucklen;
                t_remain := t_remain - t_chucklen;
                  IF t_remain < 4096
                    THEN
                    t_chucklen := t_remain;
                  END IF;

                END LOOP;
                UTL_FILE.FCLOSE (t_output);

              END;  

          END LOOP;

        END;
END;

Answer 1

检查并确保已注册对象图的所有依赖项，以便可以正确解析它们。

您很可能会丢失依赖项注册。

对于TransactionService，您要在构造函数中传递/注入实现

public TransactionService(MRepository mRepository, FService fService) {
    _mRepository = mRepository;
    _fservice = fService;
}

仅注册接口时。

container.RegisterType<IFService, FService>(new HierarchicalLifetimeManager());
container.RegisterType<IMService, MService>(new HierarchicalLifetimeManager());
container.RegisterType<ITransactionService, TransactionService>(new HierarchicalLifetimeManager());
container.RegisterType<IMRepository, MRepository>();

解析器将基于已知的依赖项对实现进行实际的初始化和注入。

更改

public TransactionService(MRepository mRepository, FService fService)

依靠注册接口

private readonly IMRepository mRepository;
private readonly IFService fService;

public TransactionService(IMRepository mRepository, IFService fService) {
    this.mRepository = mRepository;
    this.fservice = fService;
}

需要检查每个与创建/解析控制器有关的类，以确保可以正确解决它们的依赖关系。

统一依赖性错误-确保控制器具有无参数的公共构造函数

1 个答案: