代码如下
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.Threading;

namespace 服务器端
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
}
public delegate void UpdateRichEditCallback (String text);
public delegate void UpdateClientListCallback();
public delegate AsyncCallback pfnWorkerCallBack();
private Socket mainSocket();
//记录客户的Socket
private System.Collections.ArrayList workerSocketList=
ArrayList.Synchronized(new System.Collections.ArrayList());
private int clientNum=0;
}


错误提示是：上面加粗的： 应输入 class、delegate、enum、interface 或 struct D:\服务器端\服务器端\Form1.cs 30 15 服务器端
请问这是怎么回事？怎么改？我是按照书上面的例子练习的。如何处理呢？