private void btnLichlamviec_ItemClick(object sender, ItemClickEventArgs e)
 {
     pnHienthi.Controls.Clear();
     ucLichlamviec lichlamviec = new ucLichlamviec();
     pnHienthi.Controls.Add(lichlamviec);
     lichlamviec.Dock = System.Windows.Forms.DockStyle.Fill;
 }
        private void btnLichlamviec_ItemClick(object sender, ItemClickEventArgs e)
        {
            pnHienthi.Controls.Clear();
            ucLichlamviec lichlamviec = new ucLichlamviec();

            pnHienthi.Controls.Add(lichlamviec);
            lichlamviec.Dock = System.Windows.Forms.DockStyle.Fill;
        }