using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.IO;
using System.Threading;

namespace WebRequestSample
{
    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);

        public Form1()
        {
            InitializeComponent();
        }
        //WebClient client = new WebClient();
        //Uri siteUri = null;
        private void DownloadButton_Click(object sender, EventArgs e)
        {

            if ((URLTextBox.Text.IndexOf("http://")) == -1)
                MessageBox.Show("Invalid URL");
            else
            {
                saveFileDialog1.OverwritePrompt = true;
                saveFileDialog1.FileName = "Enter File Name";
                DialogResult result = saveFileDialog1.ShowDialog();
                if (result == DialogResult.OK)
                {
                    ProgressLabel.Text = "Download Starting";
                    thrDownload = new Thread(new ThreadStart(Download));
                    thrDownload.Start();
                }
            }
        }

        private void UpdateProgress(Int64 BytesRead, Int64 TotalBytes)
        {
            PercentProgress = Convert.ToInt32((BytesRead * 100) / TotalBytes);
            DownloadProgressBar.Value = PercentProgress;
            ProgressLabel.Text = "Downloaded " + BytesRead + " out of " + TotalBytes + " (" +
               PercentProgress + "%)";
        }

        private void Download()
        {

            using (WebClient wcDownload = new WebClient())
            {
                try
                {
                    webRequest = (HttpWebRequest)WebRequest.Create(URLTextBox.Text);
                    webRequest.Credentials = CredentialCache.DefaultCredentials;
                    webResponse = (HttpWebResponse)webRequest.GetResponse();
                    Int64 fileSize = webResponse.ContentLength;

                    strResponse = wcDownload.OpenRead(URLTextBox.Text);
                    strLocal = new FileStream(saveFileDialog1.FileName, FileMode.Create, FileAccess.Write,
                        FileShare.None);

                    int byteSize = 0;
                    byte[] downloadBuffer = new byte[2048];

                    while ((byteSize = strResponse.Read(downloadBuffer, 0, downloadBuffer.Length)) > 0)
                    {
                        strLocal.Write(downloadBuffer, 0, byteSize);
                        this.Invoke(new UpdateProgessCallback(this.UpdateProgress), new object[] {
                            strLocal.Length,fileSize});
                    }
                }
                finally
                {
                    strResponse.Close();
                    strLocal.Close();
                }
            }
        }

        private void StopButton_Click(object sender, EventArgs e)
        {
            ProgressLabel.Text = "Download Stopped";
            webResponse.Close();
            strResponse.Close();
            strLocal.Close();
            // Abort the thread that's downloading
            thrDownload.Abort();
            // Set the progress bar back to 0 and the label
            DownloadProgressBar.Value = 0;
        }

    }
}