public void AddDownload(string version, string size, string url, string path)
        {
            DownloadControl downloadControl = new DownloadControl(version, size, url, path);

            downloadControl.DownloadCompleted += DownloadCompleted;
            downloadControl.StopDownloadEvent += StopDownloadEvent;
            downloadControl.StartDownload();
            controlList1.Add(downloadControl);
        }
 private void button1_Click(object sender, EventArgs e)
 {
     if (MessageBox.Show("您確定要結束目前正在進行的下載?", "詢問", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.No)
     {
         return;
     }
     for (int i = 0; i < controlList1.list.Count; i++)
     {
         DownloadControl a = (DownloadControl)controlList1.list[i];
         a.StopDownload();
     }
     controlList1.Clear();
 }