有幸購買到Visual studio .net 的光碟，急忙安裝一套，一用感覺非常好，所學寫埠掃描程式一隻，獻給本版的朋友們：）
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
{
//該處放的是程式要用到的公共變數
public string scanHost = Dns.GetHostName(); //預設當前本機IP
public Int32 tport = 0; //當前連線埠編號
public Int32 connState = 0; //掃描狀態
public int portSum = 0 ; //埠總計
public bool endThread = false; //結束狀態
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;
/*
此處省略了各個呼叫的控制元件的屬性設定程式碼
*/
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("請輸入一個主機的名稱吧！","系統提示");
txtHostname.Text = scanHost.ToString();
txtHostname.Focus();
return;
}
if(startPort>endPort)
{
MessageBox.Show("錯誤，起始埠必須要小於結束的埠!","系統提示");
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("請輸入正確的主機地址,該地址DNS無法解析","系統提示");
return ;
}
logList.Items.Clear();

for (Int32 threadNum = startPort; threadNum <=endPort; threadNum++)
{
ThreadPool.QueueUserWorkItem(new WaitCallback(Startscan),threadNum);
logList.Items.Add ("掃描埠:" + threadNum.ToString());
}

}
}
public void Startscan(Object state)
{
Int32 port = (Int32) state;
string tMsg = "";
string getData = "";
int lindex = 0;
int eindex = 0;
connState++; //判斷執行緒數目
if(endThread==true)
{
if(connState==((Int32)eNum.Value-(Int32)sNum.Value))
{
cmdExec.Text = "&Scan";
logList.Items.Add ("掃描完畢!");
}
else
{
cmdExec.Text = "&Stop";
logList.Items.Add ("正在停止對"+port.ToString()+"埠的掃描執行緒");
}
logList.Items.Add("結束執行緒:"+port.ToString());
asyncOpsAreDone.Close();
}
else
{
try
{
TcpClient tcp = new TcpClient();
tcp.Connect(scanHost,port);
//該處如果建立連線錯誤的話，將不執行下面的程式碼..
portSum ++;
lindex = portList.Items.Add(port.ToString() + "埠開放",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() + "埠資料:"+getData.ToString();
eindex = portList.Items.Add(tMsg); //插入一條資訊記錄
portList.Items.Insert(lindex+1,tMsg);
portList.Items.RemoveAt(eindex);
}
sr.Close();
sm.Close();
tcp.Close();
}
catch
{
//顯示壞死的埠
if(showdie.Checked==true)
{
portList.Items.Add(port.ToString()+"埠無法連線,回傳資料為空");
}
}
finally
{
Thread.Sleep(0);
logList.Items.Add("結束執行緒:"+port.ToString());
asyncOpsAreDone.Close();
statusBar1.Text = "埠總計:"+portSum.ToString() ;
if(connState==((Int32)eNum.Value-(Int32)sNum.Value))
{
cmdExec.Text = "&Scan";
}
}
}
}

private void button1_Click(object sender, System.EventArgs e)
{
Application.Exit();
}

總結：基於.Net 框架開發程式確實簡單方便，並且功能強大。
下載程式碼與執行檔案：http://202.103.224.224/icools/bbs/non-cgi/usr/5_5.zip