public override string ToString()
{
StringBuilder sb = new StringBuilder ();
JsonWriter writer = new JsonWriter (sb);
writer.WriteObjectStart ();
writer.WritePropertyName ("option");
writer.Write (option);
writer.WritePropertyName ("subfield");
writer.Write (subfield);
writer.WritePropertyName ("tarId");
writer.Write (tarId);
writer.WriteObjectEnd ();
return sb.ToString();
}