阅读提示：   using System;
  using System.Drawing;
  using System.Collections;
  using System.ComponentModel;
  using System.Windows.Forms;
  //增加的如下..
  using System.Data;
  using System.Net.Sockets;
  using System.Net;
  using System.IO;
  using System.Text;
  using System.Threading;
  
  namespace iPortScan
  {
  /// <summary>
  /// Summary description for Form1.
  /// </summary>
  public class Form1 : System.Windows.Forms.Form
  {
   //该处放的是程序要用到的公共变量
  public string scanHost = Dns.GetHostName(); //默认当前本机IP
  public Int32 tport = 0; //当前连接端口编号
  public Int32 connState = 0; //扫描状态
  public int portSum = 0 ; //端口总计
  public bool endThread = false; //结束状态
  public AutoResetEvent asyncOpsAreDone = new AutoResetEvent(false);
  private System.Windows.Forms.Label label1;
  private System.Windows.Forms.TextBox txtHostname;
  private System.Windows.Forms.Button cmdExec;
  private System.Windows.Forms.ListBox logList;
  public System.Windows.Forms.CheckedListBox portList;
  private System.Windows.Forms.Label label2;
  private System.Windows.Forms.Label label3;
  private System.Windows.Forms.NumericUpDown sNum;
  private System.Windows.Forms.NumericUpDown eNum;
  private System.Windows.Forms.CheckBox showdie;
  private System.Windows.Forms.Label label4;
  private System.Windows.Forms.Button button1;
  private System.Windows.Forms.ToolTip toolTip1;
  private System.Windows.Forms.StatusBar statusBar1;
  private System.Windows.Forms.LinkLabel linkLabel1;
  private System.Windows.Forms.LinkLabel linkLabel2;
  private System.ComponentModel.IContainer components;
   /*
   此处省略了各个调用的控件的属性设置代码
   */
  static void Main()
  {
  Application.Run(new Form1());
  }
  
  private void cmdExec_Click(object sender, System.EventArgs e)
  {
  Int32 startPort = (Int32)sNum.Value;
  Int32 endPort = (Int32)eNum.Value;
  if(txtHostname.Text.Length==0)
  {
  MessageBox.Show("请输入一个主机的名称吧！","系统提示");
  txtHostname.Text = scanHost.ToString();
  txtHostname.Focus();
  return;
  }
  if(startPort>endPort)
  {
  MessageBox.Show("错误，起始端口必须要小于结束的端口!","系统提示");
  startPort = endPort-1;
  sNum.Text = startPort.ToString();
  sNum.Focus();
  return ;
  }
  
  if(cmdExec.Text=="&Scan")
  {
  endThread= false;
  cmdExec.Text= "&Stop";
  }
   else
  {
  endThread= true;
  cmdExec.Text= "&Scan";
  }
  
  if(endThread!=true)
  {
  connState = 0;
  portSum = 0;
  scanHost = txtHostname.Text;
  try
  {
  IPAddress ipaddr =(IPAddress)Dns.Resolve(scanHost).AddressList.GetValue(0);
  txtHostname.Text = ipaddr.ToString();
  }
  catch
  {
  txtHostname.Focus();
  MessageBox.Show("请输入正确的主机地址,该地址DNS无法解析","系统提示");
  return ;
  }
  logList.Items.Clear();
  
  for (Int32 threadNum = startPort; threadNum <=endPort; threadNum++)
  {
  ThreadPool.QueueUserWorkItem(new WaitCallback(Startscan),threadNum);
  logList.Items.Add ("扫描端口:" + threadNum.ToString());
  }
  
  }
  }
  public void Startscan(Object state)
  {
  Int32 port = (Int32) state;
  string tMsg = "";
  string getData = "";
  int lindex = 0;
  int eindex = 0;
  connState++; //判断线程数目
  if(endThread==true)
  {
  if(connState==((Int32)eNum.Value-(Int32)sNum.Value))
  {
  cmdExec.Text = "&Scan";
  logList.Items.Add ("扫描完毕!");
  }
  else
  {
  cmdExec.Text = "&Stop";
  logList.Items.Add ("正在停止对"+port.ToString()+"端口的扫描线程");
  }
  logList.Items.Add("结束线程:"+port.ToString());
  asyncOpsAreDone.Close();
  }
  else
  {
  try
  {
  TcpClient tcp = new TcpClient();
  tcp.Connect(scanHost,port);
  //该处如果建立连接错误的话，将不执行下面的代码..
  portSum ++;
  lindex = portList.Items.Add(port.ToString() + "端口开放",false);
  portList.SelectedIndex=lindex;
  Stream sm = tcp.GetStream();
  sm.Write(Encoding.Default.GetBytes(tMsg.ToCharArray()),0,tMsg.Length);
  StreamReader sr = new StreamReader(tcp.GetStream(),Encoding.Default);
  getData = sr.ReadLine();
  if(lindex!=0&&getData.Length!=0)
  {
  tMsg = " +-" + port.ToString() + "端口数据:"+getData.ToString();
  eindex = portList.Items.Add(tMsg); //插入一条信息记录
  portList.Items.Insert(lindex+1,tMsg);
  portList.Items.RemoveAt(eindex);
  }
  sr.Close();
  sm.Close();
  tcp.Close();
  }
  catch
  {
  //显示坏死的端口
  if(showdie.Checked==true)
  {
  portList.Items.Add(port.ToString()+"端口无法连接,回传数据为空");
  }
  }
  finally
  {
  Thread.Sleep(0);
  logList.Items.Add("结束线程:"+port.ToString());
  asyncOpsAreDone.Close();
  statusBar1.Text = "端口总计:"+portSum.ToString() ;
  if(connState==((Int32)eNum.Value-(Int32)sNum.Value))
  {
  cmdExec.Text = "&Scan";
  }
  }
  }
  }
  
  private void button1_Click(object sender, System.EventArgs e)
  {
  Application.Exit();
  }
  
  总结：基于.Net 框架开发程序确实简单方便，并且功能强大。 

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