/// <summary>
/// hiển thị các lớp lên combobox
/// </summary>
public void HienThiLop()
{
List <DTO_LopHoc> dt = busLopHoc.bgetlistLopHoc();
cboLop.DataSource = dt;
cboLop.DisplayMember = "TENLOP";
cboLop.ValueMember = "MALOP";
}
void HienThiTrongCombobox()
{
lNamHoc = busNamHoc.bgetListNamHoc();
cbNamHoc.DataSource = lNamHoc;
cbNamHoc.DisplayMember = "tennh";
cbNamHoc.ValueMember = "manh";
lLopHoc = busLopHoc.bgetlistLopHoc();
cbLopHoc.DataSource = lLopHoc;
cbLopHoc.DisplayMember = "tenlop";
cbLopHoc.ValueMember = "malop";
}