判断是否联网

usingSystem;
usingSystem.Collections.Generic;
usingSystem.ComponentModel;
usingSystem.Data;
usingSystem.Drawing;
usingSystem.Linq;
usingSystem.Text;
usingSystem.Text.RegularExpressions;
usingSystem.Windows.Forms;
usingSystem.Net;

namespaceWindowsFormsApplication1
{
publicpartialclassForm1:Form
{
publicForm1()
{
InitializeComponent();
}

privatevoid button1_Click(object sender,EventArgs e)
{
WebClient wb =newWebClient();
String strIP ="";
String strContent ="";
Regex regIP =newRegex("\\d{1,3}.\\d{1,3}.\\d{1,3}.\\d{1,3}");
try
{
strContent = wb.DownloadString("http://www.ip138.com/ips8.asp");
if(strContent.IndexOf("IP地址查询")>=1)
{
textBox1.Text="爽,可以上网!";
strIP = regIP.Match(strContent).ToString();
if(strIP.Trim()!="")
{
textBox2.Text="俺的IP是:"+ strIP;
}
else
{
textBox2.Text="虽然俺上网了,但是俺是黑户,没IP!";
}
}
}
catch
{
textBox1.Text="真不爽,不能上网,我去炸了电信!";
textBox2.Text="不能上网,没IP!";
}
}
}
}