using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Net;namespace test1{ public partial class Form1 : Form {  public Form1()  {   InitializeComponent();  }  private void buttonDns_Click(object sender, EventArgs e)  {   try   {    this.Cursor = Cursors.WaitCursor;    //解析主機名    IPHostEntry IPinfo = Dns.GetHostEntry(textBox1.Text);    //清空列表框    listBox1.Items.Clear();    listBox2.Items.Clear();    //顯示IP地址    foreach (IPAddress IP in IPinfo.AddressList)    {     listBox1.Items.Add(IP.ToString());    }    //顯示別名    foreach (string alias in IPinfo.Aliases)    {     listBox2.Items.Add(alias);    }    //顯示主機名    textBox2.Text = IPinfo.HostName;   }   catch (Exception ex)   {    MessageBox.Show(ex.Message);   }   finally   {    this.Cursor = Cursors.Default;   }  }  private void Form1_Load(object sender, EventArgs e)  {  } }}