private void updateScanStatus()
{
long ccount = stp.WorkItemsItemsProcessed();
long speed = ccount - lastcount;
lastcount = ccount;
this.lbl_usedtime.Text = this.scanTime.ToString();
this.lbl_waitCount.Text = (allscanCount - ccount).ToString();
this.lbl_scanedCount.Text = ccount.ToString();
this.lbl_speed.Text = speed.ToString();
}