How do I save this serialized data

String connStr = ConfigurationManager.ConnectionStrings["MDFserializerdb"].ConnectionString;
            String cmdStr = "SELECT * FROM [Table1];";
            DataSet ds = new DataSet();
            DataTable dt = new DataTable();
            try
            {
                using (SqlConnection conn = new SqlConnection(connStr))
                {
                    using (SqlCommand cmd = new SqlCommand(cmdStr, conn))
                    {
                        conn.Open();
                        SqlDataAdapter da = new SqlDataAdapter(cmd);
                        da.Fill(ds);
                        dt = ds.Tables[0];
                        System.Web.Script.Serialization.JavaScriptSerializer serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
                        List<Dictionary<string, object>> rows = new List<Dictionary<string, object>>();
                        Dictionary<string, object> row;
                        foreach (DataRow dr in dt.Rows)
                        {
                            row = new Dictionary<string, object>();
                            foreach (DataColumn col in dt.Columns)
                            {
                                row.Add(col.ColumnName, dr[col]);
                            }
                            rows.Add(row);
                        } 
                        String obj = serializer.Serialize(rows);
                        conn.Close();
                        cmd.Dispose();
                        conn.Dispose();
                    }
                }
            }
            catch (Exception ex)
            {
                Label2.Text = ex.ToString();
            }
            FileWriter file = new FileWriter("c:\\path\\test.json");
            file.write(obj.ToJSONString());
            file.flush();
            file.close();