如何使用 .Net Remoting 实现定向广播

相对于 WebService而言，使用.Net Remoting技术的客户端能够订阅服务器端事件。

利用该技术作一个简单而又典型的应用，信息广播程序是一个不错的选择。
以下代码是一个简单的广播程序。

服务端：

代码：
class Program
{
static void Main(string[] args)
{
BinaryServerFormatterSinkProvider sfsp = new BinaryServerFormatterSinkProvider();
sfsp.TypeFilterLevel = TypeFilterLevel.Full;
Hashtable props = new Hashtable();
props["port"] = 8086;
TcpChannel channel = new TcpChannel(props, null, sfsp);
ChannelServices.RegisterChannel(channel, false);
SayHello sayHello = new SayHello();
RemotingServices.Marshal(sayHello, "SayHello");
Console.ReadKey();
sayHello.Say("Mike", "Hello, Mike");
Console.ReadKey();
sayHello.Say("John", "Hello, John");
Console.ReadKey();
}
}

客户端：

代码：
class Program
{
static void Main(string[] args)
{
BinaryServerFormatterSinkProvider sfsp = new BinaryServerFormatterSinkProvider();
sfsp.TypeFilterLevel = TypeFilterLevel.Full;
Hashtable props = new Hashtable();
props["port"] = 0;
TcpChannel channel = new TcpChannel(props, null, sfsp);
ChannelServices.RegisterChannel(channel, false);
SayHello sh = (SayHello)Activator.GetObject(typeof(SayHello), "tcp://localhost:8086/SayHello");

SayEventReappear re = new SayEventReappear();
re.ClientId = "John";
sh.OnSay += new SayHandler(re.Say);
re.OnSay += new SayHandler(re_OnSay);
Console.ReadKey();
}
static void re_OnSay(string text)
{
Console.WriteLine(text);
}
}

远程对象、委托及事件重现器(需同时部署在服务端及客户端)：

代码：
public class SayHello : MarshalByRefObject
{
public event SayHandler OnSay;
public void Say(string clientId, string text)
{
if (this.OnSay != null) this.OnSay(text);
}
}
public delegate void SayHandler(string text);
public class SayEventReappear : MarshalByRefObject
{
public event SayHandler OnSay;
public void Say(string text)
{
if (this.OnSay != null) this.OnSay(text);
}
}

信息广播程序就这样完成了。