private void btnSinhlieuThetrang_ItemClick(object sender, ItemClickEventArgs e)
        {
            pnHienthi.Controls.Clear();
            ucSinhlieu sinhlieu = new ucSinhlieu();

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