Mesen-X/GUI.NET/Forms/frmDownloadProgress.cs

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

namespace Mesen.GUI.Forms
{
	public partial class frmDownloadProgress : BaseForm
	{
		private string _link;
		private string _filename;
		private bool _cancel = false;

		public frmDownloadProgress(string link, string filename)
		{
			InitializeComponent();

			_link = link;
			_filename = filename;

			try {
				File.Delete(_filename);
			} catch {}

			lblFilename.Text = link;

			tmrStart.Start();
		}

		protected override void OnClosing(CancelEventArgs e)
		{
			_cancel = true;
			base.OnClosing(e);
		}

		private void tmrStart_Tick(object sender, EventArgs e)
		{
			tmrStart.Stop();
			
			DialogResult result = System.Windows.Forms.DialogResult.None;
	
			using(var client = new WebClient()) {
				client.DownloadProgressChanged += (object s, DownloadProgressChangedEventArgs args) => {
					progressDownload.Value = args.ProgressPercentage;
				};
				client.DownloadFileCompleted += (object s, AsyncCompletedEventArgs args) => {
					if(!args.Cancelled && args.Error == null && File.Exists(_filename)) {
						result = System.Windows.Forms.DialogResult.OK;
					} else if(args.Error != null) {
						MesenMsgBox.Show("UnableToDownload", MessageBoxButtons.OK, MessageBoxIcon.Error, args.Error.ToString());
						result = System.Windows.Forms.DialogResult.Cancel;
					}
				};

				Task downloadTask = null;
				try {
					downloadTask = client.DownloadFileTaskAsync(_link, _filename);
				} catch(Exception ex) {
					MesenMsgBox.Show("UnableToDownload", MessageBoxButtons.OK, MessageBoxIcon.Error, ex.ToString());
					result = System.Windows.Forms.DialogResult.Cancel;
				}

				if(downloadTask == null) {
					result = System.Windows.Forms.DialogResult.Cancel;
				} else {
					while(!downloadTask.IsCompleted && !_cancel) {
						System.Threading.Thread.Sleep(200);
						Application.DoEvents();
					}

					if(_cancel) {
						client.CancelAsync();
					} else if(result == System.Windows.Forms.DialogResult.None) {
						result = System.Windows.Forms.DialogResult.OK;
					}
				}
			}
			DialogResult = result;
			this.Close();
		}
	}
}