C#判断网络连接状态

本人最近做c#winform的项目，遇到了判断网络是否正常连接的问题。后来查出了以下几种方法，供大家学习参考。

1.方法一

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Windows.Forms;

using System.Net.Sockets;

using System.Threading;

namespace WindowsFormsApplication1

{

public partial class Demo : Form

{

public Demo()

{

InitializeComponent();

}

//判断

private void btpanduan_Click(object sender, EventArgs e)

{

//210.192.120.228 163网易

string ip = this.txtip.Text.ToString();

int port = Convert .ToInt32( this.txtport.Text.ToString());

bool a = panduan(ip, port );//135为本机服务端口号

if (a == true)

{

MessageBox.Show("该网络连接正常 ！");

}

else

{

MessageBox.Show("该网络连接不畅通 ！");

}

}

// 异步调用

//判断的方法

public bool panduan(string ip, int port)

{

try

{

TcpClient client = new TcpClient(ip, port);

if (client.Connected)

{

return true;

}

else

{

return false;

}

}

catch

{

return false;

}

}

}

}

2.利用 c# ping类

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 WindowsFormsApplication1

{

public partial class Demo3 : Form

{

public Demo3()

{

InitializeComponent();

}

System.Net.NetworkInformation.Ping ping = new System.Net.NetworkInformation.Ping();

System.Net.NetworkInformation.PingReply res;

//检查网络连接

private void btcheck_Click(object sender, EventArgs e)

{

string url = this.txturl.Text.ToString();

bool a = check(url);

if (a == true)

{

MessageBox.Show("连接成功！", "提示信息");

}

else

{

MessageBox.Show("连接失败！", "提示信息");

}

}

public bool check(string url)

{

try

{

res = ping.Send(url);

if (res.Status == System.Net.NetworkInformation.IPStatus.Success)

{

return true;

}

else

{

return false;

}

}

catch {

return false;

}

}

}

}

using System;
using System.Collections.Generic;
using System.Text;
using System.Net.NetworkInformation;

namespace ConsoleApplication1
{
class Program
{
public static void Main(string[] args)
{
string url = "www.baidu.com;www.sina.com;www.cnblogs.com;www.google.com;www.163.com;www.csdn.com";
string[] urls = url.Split(new char[] { ';' });
CheckServeStatus(urls);

Console.ReadKey();
}

/// <summary>
/// 检测网络连接状态
/// </summary>
/// <param name="urls"></param>
public static void CheckServeStatus(string[] urls)
{
int errCount = 0;//ping时连接失败个数

if (!LocalConnectionStatus())
{
Console.WriteLine("网络异常~无连接");
}
else if (!MyPing(urls, out errCount))
{
if ((double)errCount / urls.Length >= 0.3)
{
Console.WriteLine("网络异常~连接多次无响应");
}
else
{
Console.WriteLine("网络不稳定");
}
}
else
{
Console.WriteLine("网络正常");
}
}

#region 网络检测

private const int INTERNET_CONNECTION_MODEM = 1;
private const int INTERNET_CONNECTION_LAN = 2;

[System.Runtime.InteropServices.DllImport("winInet.dll")]
private static extern bool InternetGetConnectedState(ref int dwFlag, int dwReserved);

/// <summary>
/// 判断本地的连接状态
/// </summary>
/// <returns></returns>
private static bool LocalConnectionStatus()
{
System.Int32 dwFlag = new Int32();
if (!InternetGetConnectedState(ref dwFlag, 0))
{
Console.WriteLine("LocalConnectionStatus--未连网!");
return false;
}
else
{
if ((dwFlag & INTERNET_CONNECTION_MODEM) != 0)
{
Console.WriteLine("LocalConnectionStatus--采用调制解调器上网。");
return true;
}
else if ((dwFlag & INTERNET_CONNECTION_LAN) != 0)
{
Console.WriteLine("LocalConnectionStatus--采用网卡上网。");
return true;
}
}
return false;
}

/// <summary>
/// Ping命令检测网络是否畅通
/// </summary>
/// <param name="urls">URL数据</param>
/// <param name="errorCount">ping时连接失败个数</param>
/// <returns></returns>
public static bool MyPing(string[] urls, out int errorCount)
{
bool isconn = true;
Ping ping = new Ping();
errorCount = 0;
try
{
PingReply pr;
for (int i = 0; i < urls.Length; i++)
{
pr = ping.Send(urls[i]);
if (pr.Status != IPStatus.Success)
{
isconn = false;
errorCount++;
}
Console.WriteLine("Ping " + urls[i] + "    " + pr.Status.ToString());
}
}
catch
{
isconn = false;
errorCount = urls.Length;
}
//if (errorCount > 0 && errorCount < 3)
//  isconn = true;
return isconn;
}

#endregion
}
}

转自：http://www.2cto.com/kf/201204/128285.html