c# - How to serialize list property of a dynamic object -

i have issue serialization wcf service (json output). use dynamicobject return ligth json rest service.

this code return empty result (impossible serialize):

public dynamicjsonobject dowork() {     dynamic result = new dynamicjsonobject();     result.values = new list<int>() { 1, 2 }; } 

but code works perfectly

public dynamicjsonobject dowork() {     dynamic result = new dynamicjsonobject();     result.values = 1; } 

my dynamicjsonobject class :

[serializable] public class dynamicjsonobject : dynamicobject, iserializable {     private idictionary<string, object> dictionary { get; set; }      public dynamicjsonobject()     {         dictionary = new dictionary<string, object>();     }      public dynamicjsonobject(serializationinfo info, streamingcontext context)     {         dictionary = new dictionary<string, object>();     }      public override bool trygetmember(getmemberbinder binder, out object result)     {         var haskey = dictionary.containskey(binder.name);         result = haskey ? dictionary[binder.name] : null;         return haskey;     }      public override bool trysetmember(setmemberbinder binder, object value)     {         dictionary[binder.name] = value;         return true;     }      public void getobjectdata(serializationinfo info, streamingcontext context)     {         foreach (string key in dictionary.keys)         {             info.addvalue(key.tostring(), dictionary[key]);         }     } } 

so got error error 324 (net::err_empty_response) instead of json result {values: [1,2]}

i found solution. should declare manualy list of serializable.

in exemple, can add attribute knowntype on result object

[serializable] [knowntype(typeof(list<int>))] public class dynamicjsonobject : dynamicobject, iserializable {     ... } 

the other solution use serviceknowntype on wcf service class

[servicecontract] [serviceknowntype(typeof(list<int>))] public interface idataservice {     ... } 

for information, can use generic attribute knowntype(typeof(list)