调用WCF服务时如何触发事件（客户端）

Question

我想在每次调用WCF服务时触发一个事件。

我尝试了以下方法：

var factory = new ChannelFactory<TService>(binding, endPointAdress);

factory.Credentials.UserName.UserName = username;
factory.Credentials.UserName.Password = password;

var proxy = factory.CreateChannel();

((IContextChannel)this.Proxy).Opened += new EventHandler(FactoryOpeningEventHandler);
this.Factory.Opened += new EventHandler(FactoryOpeningEventHandler);

上面的问题是，仅在打开代理时才调用该事件，但是我想在通过该代理进行调用时（不仅是在打开时）触发该事件。 我知道没有针对IContextChannel的事件可以执行我想要的操作，因此我想采用一种解决方法。

Answer 1

首先，创建一个检查器类，该类同时实现IDispatchMessageInspector （发送时）和IClientMessageInspector （接收时）接口。

public class SendReceiveInspector : IDispatchMessageInspector, IClientMessageInspector
{

    public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
    {
        // TODO: Fire your event here if needed
        return null;
    }
    public void BeforeSendReply(ref Message reply, object correlationState)
    {
        // TODO: Fire your event here if needed
    }

    public void AfterReceiveReply(ref Message reply, object correlationState)
    {
        // TODO: Fire your event here if needed
    }

    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        // TODO: Fire your event here if needed
        return null;
    }
}

拥有检查员课程后，您必须通过行为进行注册。

public class SendReceiveBehavior : IEndpointBehavior, IServiceBehavior
{
    void IEndpointBehavior.ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        clientRuntime.MessageInspectors.Add(new SendReceiveInspector());
    }

    void IEndpointBehavior.ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        endpointDispatcher.DispatchRuntime.MessageInspectors.Add(new SendReceiveInspector());
    }

    void IEndpointBehavior.AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
    {
        // Leave empty
    }

    void IEndpointBehavior.Validate(ServiceEndpoint endpoint)
    {
        // Leave empty
    }

    void IServiceBehavior.ApplyDispatchBehavior(ServiceDescription desc, ServiceHostBase host)
    {
        foreach (ChannelDispatcher cDispatcher in host.ChannelDispatchers)
        {
            foreach (EndpointDispatcher eDispatcher in cDispatcher.Endpoints)
            {
                eDispatcher.DispatchRuntime.MessageInspectors.Add(new SendReceiveInspector());
            }
        }
    }

    void IServiceBehavior.AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters)
    {
        // Leave empty
    }

    void IServiceBehavior.Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {
        // Leave empty
    }
}

最后，您必须将该行为注册到服务描述中：

host.Description.Behaviors.Add(new SendReceiveBehavior ());
foreach (ServiceEndpoint se in host.Description.Endpoints)
    se.Behaviors.Add(new SendReceiveBehavior ());

您可以在http://msdn.microsoft.com/zh-cn/magazine/cc163302.aspx上了解有关扩展WCF的更多信息。