private void buttonSearchHire_Click(object sender, EventArgs e)
        {
            connection = new SqlConnection(cs);
            connection.Open();
            SqlCommand cmd1 = connection.CreateCommand();



            cmd1.CommandText = "select WypozyczenieID, KsiazkaID, w.CzytelnikID, DataWypozyczenia, DataOddania, Imie + ' ' + Nazwisko As Czytelnik FROM Wypozyczenie w"
                               + "join Czytelnik c on c.CzytelnikId = w.CzytelnikId"
                               + "where Imie like '"+ textBoxSearchHire.Text + "%'";


            SqlDataAdapter adapt = new SqlDataAdapter(cmd1);
            DataSet ds1 = new DataSet();
            adapt.Fill(ds1);
            dataGridHire.DataSource = ds1.Tables[0].DefaultView;
            connection.Close();
        }
    }