private void barStaticItem1_ItemClick_1(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
        {
            FormTraCuu tracuu = new FormTraCuu();

            tracuu.Show();
            tracuu.MdiParent = this;
        }
 private void btnTraCuuSV_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
 {
     if (!checkOpenTabs("Tìm kiếm sinh viên"))
     {
         TabItem    t = tabControl1.CreateTab("Tìm kiếm sinh viên");
         FormTraCuu f = new FormTraCuu();
         f.TopLevel = false;
         f.Dock     = DockStyle.Fill;
         t.AttachedControl.Controls.Add(f);
         f.Show();
         //   f.ButtonClick += new EventHandler(button1_Click);
         tabControl1.SelectedTabIndex = tabControl1.Tabs.Count - 1;
     }
 }