在容器类中具有子类型信息存在问题,原因有两个:
[JsonConverter(typeof(SubTypeClassConverter))]
public class SubTypeClassBase
{
[JsonConverter(typeof(StringEnumConverter))] // Serialize enums by name rather than numerical value
public SubType Type { get { return typeToSubType[GetType()]; } }
}
现在,每当可分配给其的对象被序列化时,自定义子类型枚举都将被序列SubTypeClassBase
化。完成此操作后,对于反序列化,您可以创建一个JsonConverter
将给定的json加载SubTypeClassBase
到临时库中JObject
,检查"Type"
属性值,并将JSON对象反序列化为适当的类。
原型实现如下:
public enum SubType
{
BaseType,
Type1,
Type2,
}
[JsonConverter(typeof(SubTypeClassConverter))]
public class SubTypeClassBase
{
static readonly Dictionary<Type, SubType> typeToSubType;
static readonly Dictionary<SubType, Type> subTypeToType;
static SubTypeClassBase()
{
typeToSubType = new Dictionary<Type,SubType>()
{
{ typeof(SubTypeClassBase), SubType.BaseType },
{ typeof(SubTypeClass1), SubType.Type1 },
{ typeof(SubTypeClass2), SubType.Type2 },
};
subTypeToType = typeToSubType.ToDictionary(pair => pair.Value, pair => pair.Key);
}
public static Type GetType(SubType subType)
{
return subTypeToType[subType];
}
[JsonConverter(typeof(StringEnumConverter))] // Serialize enums by name rather than numerical value
public SubType Type { get { return typeToSubType[GetType()]; } }
}
public class SubTypeClass1 : SubTypeClassBase
{
public string AaaField { get; set; }
}
public class SubTypeClass2 : SubTypeClassBase
{
public string ZzzField { get; set; }
}
public class SubTypeClassConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return objectType == typeof(SubTypeClassBase);
}
public override bool CanWrite { get { return false; } }
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var token = JToken.Load(reader);
var typeToken = token["Type"];
if (typeToken == null)
throw new InvalidOperationException("invalid object");
var actualType = SubTypeClassBase.GetType(typeToken.ToObject<SubType>(serializer));
if (existingValue == null || existingValue.GetType() != actualType)
{
var contract = serializer.ContractResolver.ResolveContract(actualType);
existingValue = contract.DefaultCreator();
}
using (var subReader = token.CreateReader())
{
// Using "populate" avoids infinite recursion.
serializer.Populate(subReader, existingValue);
}
return existingValue;
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}