我创建了一个包含事件的类,因此您可以跟踪下载进度:
using System;
using System.IO;
using System.Net;
using System.Net.Mime;
//event examples: https://www.tutorialsteacher.com/csharp/csharp-event
public class HttpWebRequestDownload
{
private long _totalBytesLength = 0;
private long _transferredBytes = 0;
private int _transferredPercents => (int)((100 * _transferredBytes) / _totalBytesLength);
private string _defaultDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
public string downloadedFilePath = String.Empty;
public HttpWebRequestDownload(){
//Windows 7 fix
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;
}
public void DownloadFile(string url, string destinationDirectory = default)
{
string filename = "";
if (destinationDirectory == default)
destinationDirectory = _defaultDirectory;
try
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Headers.Add("Cache-Control", "no-cache");
request.Headers.Add("Cache-Control", "no-store");
request.Headers.Add("Cache-Control", "max-age=1");
request.Headers.Add("Cache-Control", "s-maxage=1");
request.Headers.Add("Pragma", "no-cache");
request.Headers.Add("Expires", "-1");
if (!Directory.Exists(destinationDirectory))
{
Directory.CreateDirectory(destinationDirectory);
}
using (HttpWebResponse response = (HttpWebResponse)request.GetResponseAsync().Result)
{
_totalBytesLength = response.ContentLength;
string path = response.Headers["Content-Disposition"];
if (string.IsNullOrWhiteSpace(path))
{
var uri = new Uri(url);
filename = Path.GetFileName(uri.LocalPath);
}
else
{
ContentDisposition contentDisposition = new ContentDisposition(path);
filename = contentDisposition.FileName;
}
using (Stream responseStream = response.GetResponseStream())
using (FileStream fileStream = File.Create(System.IO.Path.Combine(destinationDirectory, filename)))
{
byte[] buffer = new byte[1024*1024]; // 1MB buffer
ProgressEventArgs eventArgs = new ProgressEventArgs(_totalBytesLength);
int size = responseStream.Read(buffer, 0, buffer.Length);
while (size > 0)
{
fileStream.Write(buffer, 0, size);
_transferredBytes += size;
size = responseStream.Read(buffer, 0, buffer.Length);
eventArgs.UpdateData(_transferredBytes, _transferredPercents);
OnDownloadProgressChanged(eventArgs);
}
}
}
downloadedFilePath = Path.Combine(destinationDirectory, filename);
OnDownloadFileCompleted(EventArgs.Empty);
}
catch (Exception e)
{
OnError($"{e.Message} => {e?.InnerException?.Message}");
}
}
//events
public event EventHandler<ProgressEventArgs> DownloadProgressChanged;
public event EventHandler DownloadFileCompleted;
public event EventHandler<string> Error;
public class ProgressEventArgs : EventArgs
{
public long TransferredBytes { get; set; }
public int TransferredPercents { get; set; }
public long TotalBytesLength { get; set; }
public ProgressEventArgs(long transferredBytes, int transferredPercents, long totalBytesLength)
{
TransferredBytes = transferredBytes;
TransferredPercents = transferredPercents;
TotalBytesLength = totalBytesLength;
}
public ProgressEventArgs(long totalBytesLength)
{
this.TotalBytesLength = totalBytesLength;
}
public void UpdateData(long transferredBytes, int transferredPercents)
{
TransferredBytes = transferredBytes;
TransferredPercents = transferredPercents;
}
}
protected virtual void OnDownloadProgressChanged(ProgressEventArgs e)
{
DownloadProgressChanged?.Invoke(this, e);
}
protected virtual void OnDownloadFileCompleted(EventArgs e)
{
DownloadFileCompleted?.Invoke(this, e);
}
protected virtual void OnError(string errorMessage)
{
Error?.Invoke(this, errorMessage);
}
}
这是测试示例:
static void Main(string[] args)
{
HttpWebRequestDownload hDownload = new HttpWebRequestDownload();
string downloadUrl = "http://speedtest.tele2.net/10MB.zip";
hDownload.DownloadProgressChanged += HDownloadOnDownloadProgressChanged;
hDownload.DownloadFileCompleted += delegate(object o, EventArgs args)
{
Debug.WriteLine("Download finished and saved to: "+hDownload.downloadedFilePath);
};
hDownload.Error += delegate(object o, string errMessage) { Debug.WriteLine("Error has occured !! => "+errMessage); };
hDownload.DownloadFile(downloadUrl);
}
private void HDownloadOnDownloadProgressChanged(object sender, HttpWebRequestDownload.ProgressEventArgs e)
{
Debug.WriteLine("progress: "+e.TransferredBytes+" => "+e.TransferredPercents);
}