Фильтр данных после запроса на выборку

private void comboBox4_SelectedIndexChanged(object sender, EventArgs e)
        {
            string sqlStr2 = "SELECT ID_lit, Nazv, Izdanie, Avtori,Tip_pub, Yazik, God, Stranici, Slova, Rezume, PDF FROM Literatura  INNER JOIN  Tip ON Literatura.ID_tip = Tip.ID_tip INNER JOIN Yazik_pub ON Literatura.ID_yazik = Yazik_pub.ID_yazik  where ID_user = " + comboBox4.SelectedValue + " order by ID_lit";
            dataGridView1.DataSource = getData(sqlStr2);
        }

String expression;
                 expression = "God=" + "'" + this.textBox6.Text + "'";
                 this.litBindingSource.Filter = expression;

dataGridView1.DataSource = getData(sqlStr2);

BindingSource.DataSource = getData(sqlStr2);

private void _cmbRaion_SelectedIndexChanged(object sender, EventArgs e)
        {
            string sqlStr = "SELECT surname, name, lastName, dateN, dateK, dateV  FROM Forma18.dbo.Main  where idRaion = " + _cmbRaion.SelectedValue
                + " order by surname";
            _bsMain.DataSource = data.getData(sqlStr);
        }

private void comboBox4_SelectedIndexChanged(object sender, EventArgs e)
        {
            string sqlStr2 = "SELECT ID_lit, Nazv, Izdanie, Avtori,Tip_pub, Yazik, God, Stranici, Slova, Rezume, PDF FROM Literatura  INNER JOIN  Tip ON Literatura.ID_tip = Tip.ID_tip INNER JOIN Yazik_pub ON Literatura.ID_yazik = Yazik_pub.ID_yazik  where ID_user = " + comboBox4.SelectedValue + " order by ID_lit";
            bindingSource1.DataSource = getData(sqlStr2);
        }