private void thêmLớpToolStripMenuItem_Click(object sender, EventArgs e)
{
Form fThemLop = new FormThemLopHoc();
// fThemLop.MdiParent = this;
fThemLop.ShowDialog();
}
private void btnthem_Click(object sender, EventArgs e)
{
Form fthem = new FormThemLopHoc();
var isOk = fthem.ShowDialog();
if (isOk == DialogResult.OK)
{
ResetDanhSach();
}
}