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];
}