webclient下载文件 带进度条

?

private void button1_Click(object sender, EventArgs e)

  {

      doDownload(textBox1.Text.Trim());

  }

 

  private DateTime StartTime;

  private void doDownload(string url,string fileName="")

  {

 

      label1.Text = "正在下载：" + url;//label框提示下载文件

      if (fileName.Length==0)

      {

          fileName = url.Substring(url.LastIndexOf("/") + 1);

      }

      StartTime = DateTime.Now;

      progressBar1.Value = 0;//初始化单个文件下载条

      WebClient ws = new WebClient();

      ws.DownloadProgressChanged += OnDownloadProgressChanged;

      //绑定下载事件，以便于显示当前进度

      ws.DownloadFileCompleted += OnDownloadFileCompleted;

      //绑定下载完成事件，以便于计算总进度

      ws.DownloadFileAsync(new Uri(url), Path.Combine(AppDomain.CurrentDomain.BaseDirectory, fileName));

      //调用DownloadFileAsync方法下载文件

      //DownloadFileAsync有2个重载，另一个我没搞明白最后一个参数该传什么，有哪位朋友知道的，请留言告诉我谢谢

      //upapp是我一个实体类，UpdateURL存放了下载的地址（值为http://www.harde.com.cn/SoftUpdate/）

      //Path.Combine()是一个用来连接地址的方法，我将在另一日志中详细对其介绍

  }

  /// 下载进程变更事件

  private void OnDownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)

  {

      //在网上看到有朋友这么来控制进度条，我觉得麻烦，毕竟有省事的为什么我要麻烦一番……

      //this.SetProcessBar(e.ProgressPercentage, (int)((nDownloadedTotal + e.BytesReceived) * 100 / total));

      progressBar1.Value = e.ProgressPercentage;

      var s = (DateTime.Now - StartTime).TotalSeconds;

      var sd = ReadableFilesize(e.BytesReceived/s);

      label1.Text = "下载速度"+sd+"/秒"+",已下载" + ReadableFilesize(e.BytesReceived) + "/总计" + ReadableFilesize(e.TotalBytesToReceive) ;//一个label框，用来显示当前下载的数据

  }

  /// 下载进程变更事件

  private void OnDownloadFileCompleted(object sender, AsyncCompletedEventArgs e)

  {

      MessageBox.Show("complied!");

  }

  private string ReadableFilesize(double size)

  {

      String[] units = { "B", "KB", "MB", "GB", "TB", "PB" };

      double mod = 1024.0;

      int i = 0;

      while (size >= mod)

      {

          size /= mod;

          i++;}

      return Math.Round(size) + units[i];

  }