private void txttracuu_TextChanged(object sender, EventArgs e) { if (txttracuu.Text.Trim() == "") { List <Theloai_DTO> lstTL = TheLoai_BUS.LayDSTL(); DgvTheLoai.DataSource = lstTL; } else { List <Theloai_DTO> lstTimKiem = TheLoai_BUS.TimTL(dieukien, txttracuu.Text); DgvTheLoai.DataSource = lstTimKiem; } }