This seems like very strange behavior, my guess is that it stems from DateTime not being a type that is recongnized in JSON. However, you can roll your own IDataContractSurrogate to modify the serialization/deserialization process.
To use this modify your sample code when you create the the serializer to this:
var serializer = new DataContractJsonSerializer(typeof(List<object>), null, int.MaxValue, false, new DateTimeDataContractSurrogate(), true);
Then add this class:
public class DateTimeDataContractSurrogate : IDataContractSurrogate
{
private static readonly Regex dateRegex = new Regex(@"/Date\((\d+)([-+])(\d+)\)/");
private static readonly DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
public object GetCustomDataToExport(Type clrType, Type dataContractType)
{
// not used
return null;
}
public object GetCustomDataToExport(System.Reflection.MemberInfo memberInfo, Type dataContractType)
{
// not used
return null;
}
public Type GetDataContractType(Type type)
{
// not used
return type;
}
public object GetDeserializedObject(object obj, Type targetType)
{
// for debugging
//Console.WriteLine("GetDeserializedObject: obj = {0} ({1}), targetType = {2}", obj, obj.GetType(), targetType);
// only act on List<object> types
if (obj.GetType() == typeof(List<object>))
{
var objList = (List<object>)obj;
List<object> copyList = new List<object>(); // a list to copy values into. this will be the list returned.
foreach (var item in objList)
{
string s = item as string;
if (s != null)
{
// check if we match the DateTime format
Match match = dateRegex.Match(s);
if (match.Success)
{
// try to parse the string into a long. then create a datetime and convert to local time.
long msFromEpoch;
if (long.TryParse(match.Groups[1].Value, out msFromEpoch))
{
TimeSpan fromEpoch = TimeSpan.FromMilliseconds(msFromEpoch);
copyList.Add(TimeZoneInfo.ConvertTimeFromUtc(epoch.Add(fromEpoch), TimeZoneInfo.Local));
continue;
}
}
}
copyList.Add(item); // add unmodified
}
return copyList;
}
return obj;
}
public void GetKnownCustomDataTypes(System.Collections.ObjectModel.Collection<Type> customDataTypes)
{
// not used
}
public object GetObjectToSerialize(object obj, Type targetType)
{
// for debugging
//Console.WriteLine("GetObjectToSerialize: obj = {0} ({1}), targetType = {2}", obj, obj.GetType(), targetType);
return obj;
}
public Type GetReferencedTypeOnImport(string typeName, string typeNamespace, object customData)
{
// not used
return null;
}
public System.CodeDom.CodeTypeDeclaration ProcessImportedType(System.CodeDom.CodeTypeDeclaration typeDeclaration, System.CodeDom.CodeCompileUnit compileUnit)
{
// not used
return typeDeclaration;
}
}
