private void btnTimKiem_Click(object sender, EventArgs e)
        {
            string key = txtTimKiem.Text;

            if (key.Trim() != "")
            {
                grcChungLoaiHangSearch.DataSource = ChungLoaiService.Search(key);
            }
            else
            {
                grcChungLoaiHangSearch.DataSource = ChungLoaiService.LoadDataTable();
            }
        }
 private void txtTimKiem_KeyDown(object sender, KeyEventArgs e)
 {
     if (e.KeyCode == Keys.Enter)
     {
         string key = txtTimKiem.Text;
         if (key.Trim() != "")
         {
             grcChungLoaiHangSearch.DataSource = ChungLoaiService.Search(key);
         }
         else
         {
             grcChungLoaiHangSearch.DataSource = ChungLoaiService.LoadDataTable();
         }
     }
 }