private void barThongKe_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
{
ucTK = new ThongKe();
if (!pnmain.Controls.Contains(ucTK))
{
pnmain.Controls.Add(ucTK);
}
ucTK.Dock = DockStyle.Fill;
ucTK.BringToFront();
}