public void ChangeIP()
        {
            try
            {
                //change ip
                Execute("rasdial \"宽带名称\" /d", 6000);//断开宽带
                Execute("rasdial \"宽带名称\" \"宽带账号\" \"宽带密码\"", 6000);//连接宽带
            }
            catch
            {
            }
        }       
/**/
        /// 
        /// 执行DOS命令，返回DOS命令的输出
        /// dos命令
        /// 等待命令执行的时间（单位：毫秒），如果设定为0，则无限等待
        /// 返回输出，如果发生异常，返回空字符串
        public static string Execute(string dosCommand, int milliseconds)
        {
            string output = "";     //输出字符串
            if (dosCommand != null && dosCommand != "")
            {
                Process process = new Process();     //创建进程对象
                ProcessStartInfo startInfo = new ProcessStartInfo();
                startInfo.FileName = "cmd.exe";      //设定需要执行的命令
                startInfo.Arguments = "/C " + dosCommand;   //设定参数，其中的“/C”表示执行完命令后马上退出
                startInfo.UseShellExecute = false;     //不使用系统外壳程序启动
                startInfo.RedirectStandardInput = false;   //不重定向输入
                startInfo.RedirectStandardOutput = true;   //重定向输出
                startInfo.CreateNoWindow = true;     //不创建窗口
                process.StartInfo = startInfo;
                try
                {
                    if (process.Start())       //开始进程
                    {
                        if (milliseconds == 0)
                            process.WaitForExit();     //这里无限等待进程结束
                        else
                            process.WaitForExit(milliseconds);  //这里等待进程结束，等待时间为指定的毫秒
                        output = process.StandardOutput.ReadToEnd();//读取进程的输出
                    }
                }
                catch
                {
                }
                finally
                {
                    if (process != null)
                        process.Close();
                }
            }
            return output;
        }

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }int refreshcount = 0;
        private void Form1_Load(object sender, EventArgs e)
        {
            webBrowser1.Navigate("要刷新的地址");
        }
        private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            backgroundWorker1.RunWorkerAsync();
        }
        List<string> IPS = new List<string>();
        public void RefreshBlog()
        {
            if (refreshcount > 5)//每个IP差不多可以用5次
            {
                ChangeIP();
                //判断是否连接宽带成功 即是否有两个IP(内网和外网)
                while (System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName()).AddressList.Length < 2)
                {
                    ChangeIP();
                }
                //获取外网IP并判断是否已使用过
                string ip = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName()).AddressList[1].ToString();
                while (IPS.Contains(ip))
                {
                    ChangeIP();
                    ip = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName()).AddressList[1].ToString();
                }
                IPS.Add(ip);
                refreshcount = 0;
            }
            refreshcount++;
        }
        public void ChangeIP()
        {
            try
            {
                //change ip
                Execute("rasdial \"宽带名称\" /d", 6000);//断开宽带
                Execute("rasdial \"宽带名称\" \"账号\" \"密码\"", 6000);//连接宽带
            }
            catch
            {

            }
        }