private async void btnXemTkbNgayLop_ItemClick(object sender, ItemClickEventArgs e)
        {
            if (cbxXemTheo.EditValue.ToString() == "Tiểu đoàn")
            {
                cbxXemTheo.EditValue = "Lớp";
            }
            string str = txtTkbHocKy.EditValue == null ? "" : txtTkbHocKy.EditValue.ToString();

            if (str == "" || str == "Tất cả")
            {
                txtTkbHocKy.EditValue = "Tất cả";
                TkbNgayTatCaLopForm frm = new TkbNgayTatCaLopForm(this);

                frm.MdiParent = this;
                frm.Show();
                return;
            }

            Lop lop = await apis.GetLop(HocKy, str);

            if (lop == null)
            {
                DialogResult dal = MessageBox.Show("Lớp không tồn tại", "Lỗi", MessageBoxButtons.OK);
                return;
            }
            else
            {
                List <TietHoc> tietHocs = await apis.GetTietHocsNgay(HocKy, lop, (DateTime)dateNgay.EditValue);

                TkbNgayLopForm frm = new TkbNgayLopForm(lop, (DateTime)dateNgay.EditValue, tietHocs, sizeNgay, TrucBan);
                frm.MdiParent = this;
                frm.Show();
            }
        }
 private void btnXuatExcel_ItemClick(object sender, ItemClickEventArgs e)
 {
     if (this.ActiveMdiChild == null)
     {
         ribbonIn.Enabled = false;
         return;
     }
     if (this.ActiveMdiChild.Name == "TkbNgayLopForm")
     {
         TkbNgayLopForm frm = (TkbNgayLopForm)this.ActiveMdiChild;
         frm.save();
     }
     else if (this.ActiveMdiChild.Name == "TkbHocKyLopForm")
     {
         TkbHocKyLopForm frm = (TkbHocKyLopForm)this.ActiveMdiChild;
         frm.save();
     }
     else if (this.ActiveMdiChild.Name == "TkbTuanTruongForm")
     {
         TkbTuanTruongForm frm = (TkbTuanTruongForm)this.ActiveMdiChild;
         frm.save();
     }
     else if (this.ActiveMdiChild.Name == "TkbHocKyTieuDoanForm")
     {
         TkbHocKyTieuDoanForm frm = (TkbHocKyTieuDoanForm)this.ActiveMdiChild;
         frm.save();
     }
     else if (this.ActiveMdiChild.Name == "TkbNgayTatCaLopForm")
     {
         TkbNgayTatCaLopForm frm = (TkbNgayTatCaLopForm)this.ActiveMdiChild;
         frm.save();
     }
 }