Dataview does not filter row -reg

private void txtSearch_TextChanged(object sender, EventArgs e)
{
  DataSet ds1 = new DataSet();
  // ds.Clear();
  string[] str = { "inky", "pinky" };
  ds1 = ppt.P_DS("TBL_ITEMS_SEARCH_DELETE", str);
  // dataGridView1.DataSource = ds.Tables[0];
  DataView dv = new DataView(ds1.Tables[0]);
  dv.RowFilter ="ITEMCODE = '"+  txtSearch.Text+"'";
  this. dataGridView1.DataSource = dv;
}