如何在WCF服务中注入依赖关系

Question

我正在尝试在WCF服务中注入一些业务服务。我读这真的interessting帖子：How do I pass values to the constructor on my wcf service?

而且我也做了以下内容：

自定义的ServiceHost

public class UnityServiceHost : ServiceHost 
    { 
     public UnityServiceHost(IUnityContainer container, Type serviceType, params Uri[] baseAddresses) 
      : base(serviceType, baseAddresses) 
     { 
      if (container == null) 
      { 
       throw new ArgumentNullException(nameof(container)); 
      } 

      foreach (ContractDescription contractDescription in ImplementedContracts.Values) 
      { 
       contractDescription.Behaviors.Add(new UnityInstanceProvider(serviceType, container)); 
      } 
     } 
    } 

自定义实例提供

public class UnityInstanceProvider : IInstanceProvider, IContractBehavior 
{ 
    private readonly Type m_serviceType; 
    private readonly IUnityContainer m_container; 

    public UnityInstanceProvider(Type serviceType, IUnityContainer container) 
    { 
     m_serviceType = serviceType; 
     m_container = container; 
    } 
    public object GetInstance(InstanceContext instanceContext, Message message) 
    { 
     return GetInstance(instanceContext); 
    } 
    public object GetInstance(InstanceContext instanceContext) 
    { 
     return m_container.Resolve(m_serviceType); 
    } 
    public void ReleaseInstance(InstanceContext instanceContext, object instance) 
    { 
     (instance as IDisposable)?.Dispose(); 
    } 
    public void AddBindingParameters(ContractDescription contractDescription, ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)  {  } 

    public void ApplyClientBehavior(ContractDescription contractDescription, ServiceEndpoint endpoint, ClientRuntime clientRuntime)  {  } 


    public void ApplyDispatchBehavior(ContractDescription contractDescription, ServiceEndpoint endpoint, DispatchRuntime dispatchRuntime) 
    { 
     dispatchRuntime.InstanceProvider = this; 
    } 

    public void Validate(ContractDescription contractDescription, ServiceEndpoint endpoint)  {  } 
} 

服务行为我看起来像这样：

[ServiceBehavior] 
public class MyService : IMyService 
{ 
    public ServerInformationService(ISomeDependency coreManager) 
    { 
     //... 
    } 
} 

但我不进入GetInstance，当我运行代码，我得到这个：

提供，因为它 没有无法加载为服务的服务类型有一个默认（无参数）的构造函数。要修复 问题，请向该类型添加默认构造函数，或将类型为 的实例传递给主机。

我做错了什么？它看起来像我的实例提供商甚至没有使用

Answer 1

我终于找到了解决方案。我正在将我的InstanceProvider应用于联系人而不是服务。

这是我最后的（工作）解决方案：

public class UnityServiceHost : ServiceHost 
{ 
    public UnityServiceHost(IUnityContainer container, Type serviceType, params Uri[] baseAddresses) 
     : base(serviceType, baseAddresses) 
    { 
     if (container == null) 
     { 
      throw new ArgumentNullException(nameof(container)); 
     } 
     Description.Behaviors.Add(new UnityInstanceProvider(serviceType, container)); 
    } 
} 

而且行为+实例提供：

public class UnityInstanceProvider : IInstanceProvider, IServiceBehavior 
{ 
    private readonly Type m_serviceType; 
    private readonly IUnityContainer m_container; 

    public UnityInstanceProvider(Type serviceType, IUnityContainer container) 
    { 
     m_serviceType = serviceType; 
     m_container = container; 
    } 

    public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 
    { 
    } 

    public void AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters) 
    { 
    } 

    public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 
    { 
     foreach (ChannelDispatcherBase channelDispatcherBase in serviceHostBase.ChannelDispatchers) 
     { 
      ChannelDispatcher cd = (ChannelDispatcher)channelDispatcherBase; 
      foreach (EndpointDispatcher ed in cd.Endpoints) 
      { 
       if (!ed.IsSystemEndpoint) 
       { 
        ed.DispatchRuntime.InstanceProvider = this; 
       } 
      } 
     } 
    } 

    public object GetInstance(InstanceContext instanceContext) 
    { 
     return m_container.Resolve(m_serviceType); 
    } 

    public object GetInstance(InstanceContext instanceContext, Message message) 
    { 
     return GetInstance(instanceContext); 
    } 

    public void ReleaseInstance(InstanceContext instanceContext, object instance) 
    { 
     (instance as IDisposable)?.Dispose(); 
    } 
} 

它的工作原理，因为我自托管的服务（new UnityServiceHost(...) ....，如果在IIS上，我无法创建这种行为