private void btnTim_Click(object sender, EventArgs e)
{
if ("tim" != act)
{
grpThongTin.Enabled = true;
pnInFor.Visible = false;
txtMaNV.Enabled = true;
txtMaNV.Clear();
txtMaNV.Focus();
act = "tim";
return;
}
dgvNhanVien.DataSource = myNhanVienBUL.TimNhanVienTheoMa(txtMaNV.Text);
}