Chuyên Đề Chương trình Download bằng C#

Chương trình download đây là bài tập lập trình mạng down thử bằng file: URL:http://www.winarchiver.com/WADrive28.exe path: D:WADrive28.exe nhé
namespace Mydownload
{
public partial class Form1 : Form
{
private Thread thrDownload;
private Stream strResponse;
private Stream strLocal;
private HttpWebRequest webRequest;
private HttpWebResponse webResponse;
private static int percentProgress;
private delegate void UpdateProgessCallback(Int64 BytesRead, Int64 TotalBytes);
bool pause = false;
bool setproxy = false;
private string server;
Int64 maxLength;

public Form1()
{
InitializeComponent();
}


private void UpdateProgress(Int64 BytesRead, Int64 TotalBytes)
{

percentProgress = Convert.ToInt32((BytesRead * 100)/TotalBytes);
prgDownload.Value = percentProgress;
lblProgress.Text = "Downloaded:" + BytesRead/8 + "out of" + TotalBytes/8 + "(" + percentProgress + "%)";

}
private void btnDownload_Click(object sender, EventArgs e)
{
if (setproxy == true)
{
server = btnServer.Text+":"+btnPort.Text+"/";

}

if (thrDownload != null && thrDownload.ThreadState == ThreadState.Running)
{
MessageBox.Show("Đang download file .", "Download in progress", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
lblProgress.Text = "Download Starting";
thrDownload = new Thread(new ParameterizedThreadStart(Download));
thrDownload.Start(0);
btnPauseResume.Enabled = true;
btnPauseResume.Text = "Pause";
maxLength = Int64.Parse(btnMaxlength.Text.ToString());
}
}
private void Download(object startPoint)
{
try
{

int startPointInt = Convert.ToInt32(startPoint);
webRequest = (HttpWebRequest)WebRequest.Create(textBox1.Text);
/* if (setproxy == true)
{

WebProxy proxyObject = new WebProxy(server, true);
webRequest = (HttpWebRequest)WebRequest.Create(textBox1.Text);
proxyObject =(WebProxy)webRequest.Proxy;
webRequest.AddRange(startPointInt);
proxyObject.Credentials = CredentialCache.DefaultCredentials;
webRequest.Proxy = proxyObject;
}*/
if (setproxy == true)
{
WebProxy proxyObject = new WebProxy(server, true);
webRequest.AddRange(startPointInt);
webRequest.Proxy = proxyObject;
proxyObject.Credentials = CredentialCache.DefaultCredentials;
}
else
{
webRequest.AddRange(startPointInt);
webRequest.Credentials = CredentialCache.DefaultCredentials;
}
webResponse = (HttpWebResponse)webRequest.GetResponse();
Int64 fileSize = webResponse.ContentLength;
strResponse = webResponse.GetResponseStream();


if (startPointInt == 0)
{
strLocal = new FileStream(textBox2.Text, FileMode.Create, FileAccess.Write, FileShare.None);
}
else
{
strLocal = new FileStream(textBox2.Text, FileMode.Append, FileAccess.Write, FileShare.None);
}


int bytesSize = 0;
//Bộ nhớ đệm ghi lưu trữ dự liệu từ server
byte[] downBuffer = new byte[2048];

// Dừng khi bộ đệm trống
if (downBuffer.Length < maxLength)
{
while ((bytesSize = strResponse.Read(downBuffer, 0, downBuffer.Length)) > 0)
{
strLocal.Write(downBuffer, 0, bytesSize);
this.Invoke(new UpdateProgessCallback(this.UpdateProgress), new object[] { strLocal.Length, fileSize + startPointInt });

if (pause == true)
{
MessageBox.Show("không thể down tiếp File bạn chọn", "Không thể thực hiện", MessageBoxButtons.OK, MessageBoxIcon.Error);
break;
}
}
}
else
{
MessageBox.Show("File quá lớn không thể down", "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);

}

}
finally
{

strResponse.Close();
strLocal.Close();
}
}
private void btnStop_Click(object sender, EventArgs e)
{
thrDownload.Abort();
webResponse.Close();
strResponse.Close();
strLocal.Close();
prgDownload.Value = 0;
lblProgress.Text = "Download Stopped";
btnPauseResume.Enabled = false;
}
private void btnPauseResume_Click(object sender, EventArgs e)
{

if (thrDownload != null)
{
if (btnPauseResume.Text == "Pause")
{
pause = true;
btnPauseResume.Text = "Resume";

webResponse.Close();
strResponse.Close();
strLocal.Close();
thrDownload.Abort();
}
else .