private void button4_Click(object sender, EventArgs e)
{
if (videoCapture.IsDownloading == false)
{
videoCapture.Download(sPlayBackFileName1, sPlayBackFileName2);
timerDownload.Enabled = true;
button4.Text = "停止下载";
}
else
{
videoCapture.DownloadStop();
DownloadProgressBar.Value = 0;
timerDownload.Enabled = false;
button4.Text = "回放下载";
}
}