获取网络数据流量

using System.Net.NetworkInformation;
using System.Timers;
 
namespace Monitor
{
  public class MonitorNetwork
  {   
    public string UpSpeed { get; set; }  
    public string DownSpeed { get; set; }
    public string AllTraffic { get; set; }      
    private string NetCardDescription { get; set; }  
    //建立连接时上传的数据量
    private long BaseTraffic { get; set; }  
    private long OldUp { get; set; }  
    private long OldDown { get; set; }
    private NetworkInterface networkInterface { get; set; }
    private Timer timer = new Timer() { Interval = 1000 };
   
    public void Close()
    {
      timer.Stop();  
    }
   
    public MonitorNetwork(string netCardDescription)
    {  
      timer.Elapsed += Timer_Elapsed;  
      NetCardDescription = netCardDescription;  
      timer.Interval = 1000;   
    }
 
    public bool Start()
    {
      networkInterface = null;  
      NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();  
      foreach (var var in nics)
      {
        if (var.Description.Contains(NetCardDescription))
        {
          networkInterface = var;
          break;
        }
      }  
      if (networkInterface == null)
      {
        return false;
      }
      else
      {  
        BaseTraffic = (networkInterface.GetIPStatistics().BytesSent +
                networkInterface.GetIPStatistics().BytesReceived);  
        OldUp = networkInterface.GetIPStatistics().BytesSent;  
        OldDown = networkInterface.GetIPStatistics().BytesReceived;  
        timer.Start();  
        return true;
      }
   
    }
 
    private string[] units = new string[] {"KB/s","MB/s","GB/s" };
 
    private void CalcUpSpeed()
    {
      long nowValue = networkInterface.GetIPStatistics().BytesSent;  
      int num = 0;
      double value = (nowValue - OldUp) / 1024.0;
      while (value > 1023)
      {
        value = (value / 1024.0);
        num++;
      }  
      UpSpeed = value.ToString("0.0") + units[num];  
      OldUp = nowValue;  
    }
   
    private void CalcDownSpeed()
    {
      long nowValue = networkInterface.GetIPStatistics().BytesReceived;  
      int num = 0;
      double value = (nowValue - OldDown) / 1024.0;   
      while (value > 1023)
      {
        value = (value / 1024.0);
        num++;
      }  
      DownSpeed = value.ToString("0.0") + units[num];  
      OldDown = nowValue;  
    }
   
    private string[] unitAlls = new string[] { "KB", "MB", "GB" ,"TB"};
   
    private void CalcAllTraffic()
    {
      long nowValue = OldDown+OldUp;  
      int num = 0;
      double value = (nowValue- BaseTraffic) / 1024.0;
      while (value > 1023)
      {
        value = (value / 1024.0);
        num++;
      }  
      AllTraffic = value.ToString("0.0") + unitAlls[num];
    }
 
    private void Timer_Elapsed(object sender, ElapsedEventArgs e)
    {
      CalcUpSpeed();
      CalcDownSpeed();
      CalcAllTraffic();
    }
  }
}