Update datagridview with SQL query

 string str = @"update dbo." + tblname + "";
 str += " set SettingValue = " + value + "";
 str += " where id = '" + id + "'";
 SqlCommand cm = new SqlCommand(str, MyConnection);
 MyConnection.Open();
 SqlDataReader re;
 re = cm.ExecuteReader();
 re.Close();
 MyConnection.Close();
BindGrid();

int Id =Convert.ToInt32(dataGridView1.CurrentRow.Cells["id"].Value);
 string tblname = dataGridView1.CurrentRow.Cells["TableName"].Value.ToString();
 string val = textBox1.Text;
 MyUpdate(tbl, val, Id);

private void BindGrid()
        {
            dataGridView1.DataSource = bindingSource1;
            var str = @"SELECT  B.Id,  CASE WHEN b.settingdesc IS NULL THEN b.settingkey WHEN b.settingdesc = '' THEN b.SettingKey WHEN b.settingdesc <> '' THEN b.settingDesc END AS settingdesc,
                         'SysSettingsDep' AS TableName, B.SettingValue AS settingvalue
                    FROM         SysCustomer AS A INNER JOIN
                                            SysSettingsDep AS B ON A.SettingKey = B.SettingKey
                    UNION
                    SELECT  C.Id, CASE WHEN c.settingdesc IS NULL THEN c.SettingKey WHEN c.settingdesc = '' THEN c.SettingKey WHEN c.settingdesc <> '' THEN c.settingDesc END AS settingdesc,
                            'SysSettingsMachine' AS TableName, C.SettingValue AS settingvalue
                    FROM         SysCustomer AS A INNER JOIN
                                            SysSettingsMachine AS C ON A.SettingKey = C.SettingKey
                    UNION
                    SELECT  D.Id ,  CASE WHEN d .settingdesc IS NULL THEN d .SettingKey WHEN d .settingdesc = '' THEN d .SettingKey WHEN d .settingdesc <> '' THEN d .settingDesc END AS settingdesc,
                            'SysSettings' AS TableName, D.SettingValue AS settingvalue
                    FROM         SysCustomer AS A INNER JOIN
                                            SysSettings AS D ON A.SettingKey = d.SettingKey";

 SqlDataAdapter dataAdapter = new SqlDataAdapter(selectCommand, MyConnection);
 SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dataAdapter);
 DataTable table = new DataTable();
 table.Locale = System.Globalization.CultureInfo.InvariantCulture;
 dataAdapter.Fill(table);
 bindingSource1.DataSource = table;       dataGridView1.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCellsExceptHeader);
        }