/// <summary>
/// Load all class to combobox
/// </summary>
void LoadMaLop_DSLH()
{
// if (listLop.Count == 0)
listLop = lopBLL.GetLopTheoNamHoc(cbNH_HSLH.Text);
List <string> listTenLop = new List <string>();
foreach (Lop lop in listLop)
{
listTenLop.Add(lop.TenLop);
}
cbLop_DSLH.DataSource = listTenLop;
}