C#判断网络连接问题

Question

我这里有个连接【宽带连接】，怎样可以判断这个连接是否已经连接，哪位高手帮忙解决下（详细代码）
if（???）
{
    ...
}
else
{
    ...
}
帮帮忙，谢谢！！！

Answer 1

private Socket TSocket
if(TSocket !=null)

Answer 2

        private void button1_Click(object sender, EventArgs e)
        {
            System.Diagnostics.Process p = new System.Diagnostics.Process();
            p.StartInfo.FileName = "cmd.exe";
            p.StartInfo.UseShellExecute = false;
            p.StartInfo.RedirectStandardInput = true;
            p.StartInfo.RedirectStandardOutput = true;
            p.StartInfo.RedirectStandardError = true;
            p.StartInfo.CreateNoWindow = true;
            string strOutput = null;            try
            {
                p.Start();
                p.StandardInput.WriteLine("rasdial");
                p.StandardInput.WriteLine("exit");
                strOutput = p.StandardOutput.ReadToEnd();
                p.WaitForExit();            }
            catch (Exception ex)
            {
                strOutput = ex.Message;
                System.Threading.Thread.Sleep(1000);
            }
            finally
            {
                if (p != null)
                    p.Close();
            }
            if (strOutput.IndexOf("已连接") >= 0)
            {
                MessageBox.Show("已连接");
            }
            else
            {
                MessageBox.Show("未连接");
            }
        }

Answer 3

可以参考：
http://blog.csdn.net/huangyaoshifog/archive/2009/08/24/4474834.aspx