private void barButtonItem3_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
{
formChinh.Enabled = false;
FormLenLop f = new FormLenLop(formChinh);
f.ShowDialog();
}
public FormLL10(FormLenLop formLenLop)
{
InitializeComponent();
this.formLenLop = formLenLop;
}