About datalist in json

public List<datalist7> getdata(string id)
      {
          SqlConnection con = new SqlConnection(@"Data Source=saba-PC;Initial Catalog=bcounts;Integrated Security=True");
          con.Open();
          SqlCommand cmd = new SqlCommand("Select Compcode,Acct_sub0 from GI_sub0 where Compcode='" + id + "'", con);
          SqlDataReader rdr = cmd.ExecuteReader();
          List<datalist7> data = new List<datalist7>();
          if (rdr.HasRows)
          {
             while (rdr.Read())
              data.Add(new datalist7(rdr.GetString(0), rdr.GetString(1),rdr.GetString(2),rdr.GetString(3),rdr.GetString(4),rdr.GetString(5),rdr.GetString(6)));
          }
          con.Close();
          return data;
      }

[DataContract]
    public class datalist7
    {
        [DataMember]
        public string val1 { get; set; }
        [DataMember]
        public string val2 { get; set; }
        [DataMember]
        public string val3 { get; set; }
        [DataMember]
        public string val4 { get; set; }
        [DataMember]
        public string val5 { get; set; }
        [DataMember]
        public string val6 { get; set; }
        [DataMember]
        public string val7 { get; set; }
        public datalist7(string v1, string v2, string v3, string v4, string v5, string v6, string v7)
        {
            val1 = v1;
            val2 = v2;
            val3 = v3;
            val4 = v4;
            val5 = v5;
            val6 = v6;
            val7 = v7;
        }

    }