概述
WCF陆陆续续也用过多次,但每次都是浅尝辄止,以将够解决问题为王道,这几天稍闲,特寻了些资料看,昨晚尝试使用WCF的双工模式实现了一个简单的即时通讯程序,通过服务端转发实现客户端之间的通讯。这只是个Demo,没有考虑异常处理和性能问题。解决方案结构如下:

契约
using System;
using System.Collections.Generic;
using System.Linq;
using System.ServiceModel;
using System.Text;
using System.Threading.Tasks;
namespace Service.Interface
{
[ServiceContract(CallbackContract = typeof(ICallBack))]
public interface INoticeOperator
{
[OperationContract]
void Register(String id);
[OperationContract]
void UnRegister(String id);
[OperationContract]
void SendMessage(String from, String to, String message);
}
}
该接口定义了三个行为,分别是:
•注册
•注销
•发消息
其中,在特性[ServiceContract(CallbackContract = typeof(ICallBack))]中指定了用于服务端回调客户方法的契约ICallBack,其定义如下:
using System;
using System.Collections.Generic;
using System.Linq;
using System.ServiceModel;
using System.Text;
using System.Threading.Tasks;
namespace Service.Interface
{
public interface ICallBack
{
[OperationContract(IsOneWay = true)]
void Notice(String message);
}
}
实体
本Demo只有一个实体,用来表示已经注册用户的Id和对应的回调契约的具体实现的实例:
using Service.Interface;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Models
{
public class Client
{
public String Id { get; set; }
public ICallBack CallBack { get; set; }
}
}
契约的实现代码
using Models;
using Service.Interface;
using System;
using System.Collections.Generic;
using System.Linq;
using System.ServiceModel;
using System.Text;
using System.Threading.Tasks;
namespace Service
{
public class NoticeOperator : INoticeOperator
{
private static List<Client> clientList = new List<Client>();
public void Register(string id)
{
Console.WriteLine("register:" + id);
ICallBack callBack = OperationContext.Current.GetCallbackChannel<ICallBack>();
clientList.Add(new Client() { Id = id, CallBack = callBack });
}
public void UnRegister(string id)
{
Console.WriteLine("unRegister:" + id);
Client client = clientList.Find(c => c.Id == id);
if (client != null)
{
clientList.Remove(client);
}
}
public void SendMessage(string from, string to, string message)
{
Client client = clientList.Find(c => c.Id == to);
if (client != null)
{
String longMessage = String.Format("message from {0} to {1} at {2} : {3}", from, to, DateTime.Now.ToString("HH:mm:ss"), message);
Console.WriteLine(longMessage);
client.CallBack.Notice(longMessage);
}
}
}
}










