c# - 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。

我试过以下方法:

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);

上面的问题是事件只在代理打开时调用，但我想在通过这个代理进行调用时触发事件，而不仅仅是在它打开时。我知道 IContextChannel 没有事件可以做我想做的事，所以我想有一个解决方法。

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(interface)。

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;
    }
}

在你有你的检查员类之后，你必须通过一个行为来注册它。

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您的服务描述中:

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/en-us/magazine/cc163302.aspx 了解有关扩展 WCF 的更多信息