public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (contractResolver != serializer.ContractResolver)
{
throw new InvalidOperationException("Inconsistent contract resolvers");
}
Type elementType;
JsonProperty keyProperty;
if (!CanConvert(contractResolver, objectType, out elementType, out keyProperty))
{
throw new JsonSerializationException(string.Format("Invalid input type {0}", objectType));
}
if (reader.TokenType == JsonToken.Null)
{
return(existingValue);
}
var list = existingValue as IList;
if (list == null || list.Count == 0)
{
list = list ?? (IList)contractResolver.ResolveContract(objectType).DefaultCreator();
serializer.Populate(reader, list);
}
else
{
var jArray = JArray.Load(reader);
var comparer = new KeyedListMergeComparer();
var lookup = jArray.ToLookup(i => i[keyProperty.PropertyName].ToObject(keyProperty.PropertyType, serializer), comparer);
var done = new HashSet <JToken>();
foreach (var item in list)
{
var key = keyProperty.ValueProvider.GetValue(item);
var replacement = lookup[key].Where(v => !done.Contains(v)).FirstOrDefault();
if (replacement != null)
{
using (var subReader = replacement.CreateReader())
serializer.Populate(subReader, item);
done.Add(replacement);
}
}
// Populate the NEW items into the list.
if (done.Count < jArray.Count)
{
foreach (var item in jArray.Where(i => !done.Contains(i)))
{
list.Add(item.ToObject(elementType, serializer));
}
}
}
return(list);
}
object ReadJsonGeneric <T>(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer, JsonProperty keyProperty)
{
var list = existingValue as IList <T>;
if (list == null || list.Count == 0)
{
list = list ?? (IList <T>)contractResolver.ResolveContract(objectType).DefaultCreator();
serializer.Populate(reader, list);
}
else
{
var jArray = JArray.Load(reader);
var comparer = new KeyedListMergeComparer();
var lookup = jArray.ToLookup(i => i[keyProperty.PropertyName].ToObject(keyProperty.PropertyType, serializer), comparer);
var done = new HashSet <JToken>();
foreach (var item in list)
{
var key = keyProperty.ValueProvider.GetValue(item);
var replacement = lookup[key].Where(v => !done.Contains(v)).FirstOrDefault();
if (replacement != null)
{
using (var subReader = replacement.CreateReader())
serializer.Populate(subReader, item);
done.Add(replacement);
}
}
// Populate the NEW items into the list.
if (done.Count < jArray.Count)
{
foreach (var item in jArray.Where(i => !done.Contains(i)))
{
list.Add(item.ToObject <T>(serializer));
}
}
}
return(list);
}
