WCF服务可以有构造函数吗?

时间:2008-12-19 18:41:51

标签: wcf dependency-injection constructor

当我在我的解决方案中新建一个WCF服务时,我可以执行以下操作,有一个带参数的构造函数可以传入吗?如果是,运行时如何,何时以及在何处填写我所需的IBusinessLogic对象?

[ServiceContract]
public interface IServiceContract
{
    [OperationContract]
    ...
}

public class MyService : IServiceContract
{
    IBusinessLogic _businessLogic;
    public ServiceLayer(IBusinessLogic businessLogic)
    {
        _businessLogic = businessLogic;
    }
    ...
}

6 个答案:

答案 0 :(得分:13)

开箱即用WCF只会使用默认构造函数,不能使用参数化构造函数。你必须做一些额外的工作才能使WCF调用参数化构造函数。

你可以试试这个:

  

How do I pass values to the constructor on my wcf service?

答案 1 :(得分:6)

答案 2 :(得分:6)

您可以让WCF(间接地)调用非默认构造函数,为此,您需要滚动自己的实例提供程序。您需要实现IInstanceProvider并添加自定义服务行为。一些链接将向您展示如何与Spring.NET结合使用:

WCF Service Dependency Injection

Code example WCF Service Dependency Injection

答案 3 :(得分:4)

除了其他响应之外,另一种情况是创建单例服务时 - 这是将服务实例传递给ServiceHost(而不是类型);

显然,在创建实例时,您可以使用任何构造函数;

此方法需要向您的服务添加属性:[ServiceBehavior(InstanceContextMode.Single)];

答案 4 :(得分:3)

我将@Mark Seemann的解决方案解释为通用实例提供程序行为

如何使用它:

var host = new ServiceHost(typeof(MyService), baseAddress);
var instanceProvider = new InstanceProviderBehavior<T>(() => new MyService(businessLogic));
instanceProvider.AddToAllContracts(host);

InstanceProvider行为代码:

public class InstanceProviderBehavior<T> : IInstanceProvider, IContractBehavior
    where T : class
{
  private readonly Func<T> m_instanceProvider;

  public InstanceProviderBehavior(Func<T> instanceProvider)
  {
    m_instanceProvider = instanceProvider;
  }

  // I think this method is more suitable to be an extension method of ServiceHost.
  // I put it here in order to simplify the code.
  public void AddToAllContracts(ServiceHost serviceHost)
  {
    foreach (var endpoint in serviceHost.Description.Endpoints)
    {
      endpoint.Contract.Behaviors.Add(this);
    }
  }

  #region IInstanceProvider Members

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

  public object GetInstance(InstanceContext instanceContext)
  {
    // Create a new instance of T
    return m_instanceProvider.Invoke();
  }

  public void ReleaseInstance(InstanceContext instanceContext, object instance)
  {
    try
    {
      var disposable = instance as IDisposable;
      if (disposable != null)
      {
        disposable.Dispose();
      }
    }
    catch { }
  }

  #endregion

  #region IContractBehavior Members

  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)
  {
  }

  #endregion
}

答案 5 :(得分:2)

您必须实现IInstanceProvider才能调用参数化服务构造函数。这个构造函数在生成的代理中不可用。