private void StockOutUI_Load(object sender, EventArgs e)
{
DataTable cadt = stockOutManager.GetCategoryStockOutBindingSource();
categoryStockInBindingSource.DataSource = cadt;
categoryStockOutComboBox.SelectedValue = -1;
messageLabel.Text = "";
messageLabel2.Text = "";
Notification();
timer2.Start();
dateLabel.Text = DateTime.Now.ToLongDateString();
timeLabel.Text = DateTime.Now.ToLongTimeString();
}