服務建立：

using WebSocketSharp.Server;
......
public static WebSocketServer TakeServer;
......
// 建立3個服務
TakeServer = new WebSocketServer("ws://192.168.0.103:9999");
TakeServer.AddWebSocketService<UserLOGIN>("/UserLOGIN");
TakeServer.AddWebSocketService<ToALLUSER>("/ToALLUSER");
TakeServer.AddWebSocketService<ToUSER>("/ToUSER");
TakeServer.Start();
......
public class UserLOGIN : WebSocketBehavior
{
    protected override void OnMessage(MessageEventArgs e)
    {
      ......
     }
    private static void ws_OnOpen(object sender, EventArgs e)
    {
      ......
    }
    protected override void OnClose(CloseEventArgs e)
    {
      ......
    }
}
......

附帶教程，里面有詳細說明。