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); }