C# 下载方法 - System.FormatException： 'Input string was not in a correct format'

Question

我是C#编程的新手，我正在尝试创建一个异步下载程序，因为WebClient对于一个500 Mb以上的zip文件来说太慢了。以下是我正在使用的代码，这些是我在更新进度条和标签时遇到的问题

问题代码：

if (progressBar.InvokeRequired)
{
progressBar.Invoke(new Action(() => progressBar.Show()));
progressBar.Invoke(new Action(() => progressBar.Value = int.Parse(Math.Truncate(percentage).ToString())));
}
else
{
progressBar.Invoke(new Action(() => progressBar.Show()));
progressBar.Value = int.Parse(Math.Truncate(percentage).ToString());
}
if (labelProgress.InvokeRequired)
{
labelProgress.Invoke(new Action(() => labelProgress.Show()));
labelProgress.Invoke(new Action(() => labelProgress.Text = int.Parse(Math.Truncate(percentage).ToString()).ToString()));
}
else
{
labelProgress.Invoke(new Action(() => labelProgress.Show()));
labelProgress.Text = int.Parse(Math.Truncate(percentage).ToString()).ToString();
}

代码

private void Downloader_Click(object sender, EventArgs e)
{
Downloader.Enabled = false;
backgroundWorker1.RunWorkerAsync();
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
Downloader.Enabled = true;
System.Windows.MessageBox.Show("Download Completed");
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
DownloadFileWithProgress(zipUrl, zipPath, progressBar, labelPerc);
}
private void DownloadFileWithProgress(string DownloadLink, string TargetPath, Bunifu.UI.Winforms.BunifuProgressBar progressBar, Label labelProgress)
{
int bytesProcessed = 0;
Stream remoteStream = null;
Stream localStream = null;
WebResponse response = null;
try
{
WebRequest request = WebRequest.Create(DownloadLink);
if (request != null)
{
double TotalBytesToReceive = 0;
var SizewebRequest = HttpWebRequest.Create(new Uri(DownloadLink));
SizewebRequest.Method = "HEAD";
using (var webResponse = SizewebRequest.GetResponse())
{
var fileSize = webResponse.Headers.Get("Content-Lenght");
TotalBytesToReceive = Convert.ToDouble(fileSize);
}
response = request.GetResponse();
if (response != null)
{
remoteStream = response.GetResponseStream();
string filePath = TargetPath;
localStream = File.Create(filePath);
byte[] buffer = new byte[1024];
int bytesRead = 0;
do
{
bytesRead = remoteStream.Read(buffer, 0, buffer.Length);
localStream.Write(buffer, 0, bytesRead);
bytesProcessed += bytesRead;
double bytesIn = double.Parse(bytesProcessed.ToString());
double percentage = bytesIn / TotalBytesToReceive * 100;
percentage = Math.Round(percentage, 0);
if (progressBar.InvokeRequired)
{
progressBar.Invoke(new Action(() => progressBar.Show()));
progressBar.Invoke(new Action(() => progressBar.Value = int.Parse(Math.Truncate(percentage).ToString())));
}
else
{
progressBar.Invoke(new Action(() => progressBar.Show()));
progressBar.Value = int.Parse(Math.Truncate(percentage).ToString());
}
if (labelProgress.InvokeRequired)
{
labelProgress.Invoke(new Action(() => labelProgress.Show()));
labelProgress.Invoke(new Action(() => labelProgress.Text = int.Parse(Math.Truncate(percentage).ToString()).ToString()));
}
else
{
labelProgress.Invoke(new Action(() => labelProgress.Show()));
labelProgress.Text = int.Parse(Math.Truncate(percentage).ToString()).ToString();
}
} while (bytesRead > 0);
}
}
}
catch (Exception ex)
{
}
finally
{
if (response != null) response.Close();
if (remoteStream != null) remoteStream.Close();
if (localStream != null) localStream.Close();
}
}

Answer 1

我最终使用了这个包->https://github.com/bezzad/Downloader