using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Management;

namespace Record
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
ManagementClass newClass = new ManagementClass();

//Set up an event watcher and a handler for the event
ManagementEventWatcher networkAdapterArrivalWatcher =
new ManagementEventWatcher("http://www.cnblogs.com/94cool/admin/file://root//wmi",
"SELECT * FROM MSNdis_NotifyAdapterArrival ");

ManagementEventWatcher networkAdapterRemovalWatcher =
new ManagementEventWatcher("http://www.cnblogs.com/94cool/admin/file://root//wmi",
"SELECT * FROM MSNdis_NotifyAdapterRemoval ");

MyHandler handler = new MyHandler();
networkAdapterArrivalWatcher.EventArrived += new EventArrivedEventHandler(handler.Arrived);
networkAdapterRemovalWatcher.EventArrived += new EventArrivedEventHandler(handler.Removed);
//Start watching for events
networkAdapterArrivalWatcher.Start();
networkAdapterRemovalWatcher.Start();
//while (true)
// System.Threading.Thread.Sleep(200000);
//IsNetworkAvailable;
}
}
public class MyHandler
{
public void Arrived(object sender, EventArrivedEventArgs e)
{
Console.WriteLine("Network connected");
}

public void Removed(object sender, EventArrivedEventArgs e)
{
Console.WriteLine("Network disconnected");
}
}
}

本文转自94cool博客园博客，原文链接：http://www.cnblogs.com/94cool/archive/2009/08/14/1545775.html，如需转载请自行联系原作者