ASPNET Core ActionResult property not serialize - asp.net-core

Question

I have this object
[DataContract]
public class FilterList<T> : List<T>
{
[DataMember]
public int Total { get; set; }
}
In my controller:
public ActionResult<FilterList<MyPOCO>> GetFilteredResult(string filter)
{
var l = new FilterList<MyPOCO>();
l.Total = 123456;
// Continue to add many MyPOCO objects into the list
return l;
}
I can get back the MyPOCO list at the client side, but the l.Total is NOT serialize. May I know what I had done wrongly?

Answer 1

Here is a workaround , you could try to use [JsonObject] attribute . But the items will not be serialized, because a JSON container can have properties, or items -- but not both. If you want both, you will need to add a synthetic list property to hold the items.
[JsonObject] will also cause base class properties such as Capacity to be serialized, which you likely do not want. To suppress base class properties, use MemberSerialization.OptIn. Thus your final class should look something like:
[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
public class FilterList<T> : List<T>
{
[JsonProperty]
public int Total { get; set; }
[JsonProperty]
List<T> Items
{
get
{
return this.ToList();
}
set
{
if (value != null)
this.AddRange(value);
}
}
}
Result: