我有一个托管WCF服务的控制台应用程序。我希望能够从WCF服务中的方法触发事件，并在WCF服务的托管过程中处理该事件。这可能吗？我该怎么做？我可以从ServiceHost派生自定义类吗？

解决方案

我们无需从ServiceHost继承。还有其他方法可以解决问题。

我们可以将服务类的实例(而不是类型)传递给ServiceHost。因此，我们可以在启动ServiceHost之前创建实例，并将我们自己的事件处理程序添加到它公开的任何事件中。

这里是一些示例代码：

MyService svc = new MyService();
svc.SomeEvent += new MyEventDelegate(this.OnSomeEvent);
ServiceHost host = new ServiceHost(svc);
host.Open();

如http://msdn.microsoft.com/en-us/library/ms585487.aspx中所述，使用此方法时有一些注意事项

或者，我们可以有一个众所周知的单例类，服务实例知道该类，并在事件发生时显式调用其方法。

using ...
using ...

namespace MyWCFNamespace
{
    class Program {

        static void Main(string[] args){
            //instantiate the event receiver
            Consumer c = new Consumer();

            // instantiate the event source
            WCFService svc = new WCFService();
            svc.WCFEvent += new SomeEventHandler(c.ProcessTheRaisedEvent);

            using(ServiceHost host = new ServiceHost(svc))
            {
                host.Open();
                Console.Readline();
            }
        }
    }

    public class Consumer()
    {
        public void ProcessTheRaisedEvent(object sender, MyEventArgs e)
        {
            Console.WriteLine(e.From.toString() + "\t" + e.To.ToString());
        }
    }
}

namespace MyWCFNamespace
{
    public delegate void SomeEventHandler(object sender,MyEventArgs e)

    [ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)]
    public class WCFService : IWCFService 
    {
        public event SomeEventHandler WCFEvent;

        public void someMethod(Message message)
        {
            MyEventArgs e = new MyEventArgs(message);
            OnWCFEvent(e);
        }

        public void OnWCFEvent(MyEventArgs e)
        {
            SomeEventHandler handler = WCFEvent;
            if(handler!=null)
            {
                handler(this,e);
            }
        }

    // to do 
    // Implement WCFInterface methods here
    }

    public class MyEventArgs:EventArgs
    {
        private Message _message;
        public MyEventArgs(Message message) 
        {
            this._message=message;
        }
    }
    public class Message
    {
        string _from;
        string _to;
        public string From {get{return _from;} set {_from=value;}}
        public string To {get{return _to;} set {_to=value;}}
        public Message(){}
        public Message(string from,string to)
        this._from=from;
        this._to=to;
    }
}

我们可以使用InstanceContextMode = InstanceContextMode.Single定义WCF服务。

TestService svc = new TestService();
svc.SomeEvent += new MyEventHandler(receivingObject.OnSomeEvent);
ServiceHost host = new ServiceHost(svc);
host.Open();

[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)] // so that a single service instance is created
    public class TestService : ITestService
    {
        public event MyEventHandler SomeEvent;
        ...
        ...
    }