Dictionary<string, List<int>>
是集合的嵌套集合,您正在寻找类似于 的东西ItemOfItemsConverterType
,对应于ItemConverterType
,为集合的项目的项目指定转换器。不幸的是,没有实现这样的属性。相反,有必要为List<int>
调用所需的最内层项转换器的嵌套集合创建一个转换器。
这可以通过实现以下JsonConverter
装饰器来完成List<>
:
public class ListItemConverterDecorator : JsonConverter
{
readonly JsonConverter itemConverter;
public ListItemConverterDecorator(Type type) =>
itemConverter = (JsonConverter)Activator.CreateInstance(type ?? throw new ArgumentNullException());
public override bool CanConvert(Type objectType) =>
!objectType.IsPrimitive && objectType != typeof(string) && objectType.BaseTypesAndSelf().Any(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(List<>));
public override bool CanRead => itemConverter.CanRead;
public override bool CanWrite => itemConverter.CanWrite;
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var itemType = objectType.BaseTypesAndSelf().Where(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(List<>)).Select(t => t.GetGenericArguments()[0]).First();
if (reader.MoveToContentAndAssert().TokenType == JsonToken.Null)
return null;
if (reader.TokenType != JsonToken.StartArray)
throw new JsonSerializationException(string.Format("Unexpected token {0}, expected {1}", reader.TokenType, JsonToken.StartArray));
var list = existingValue as IList ?? (IList)serializer.ContractResolver.ResolveContract(objectType).DefaultCreator();
while (reader.ReadToContentAndAssert().TokenType != JsonToken.EndArray)
list.Add(itemConverter.ReadJson(reader, itemType, null, serializer));
return list;
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
writer.WriteStartArray();
foreach (var item in (IList)value)
if (item == null)
writer.WriteNull();
else
itemConverter.WriteJson(writer, item, serializer);
writer.WriteEndArray();
}
}
public static partial class JsonExtensions
{
public static JsonReader ReadToContentAndAssert(this JsonReader reader) =>
reader.ReadAndAssert().MoveToContentAndAssert();
public static JsonReader MoveToContentAndAssert(this JsonReader reader)
{
if (reader == null)
throw new ArgumentNullException();
if (reader.TokenType == JsonToken.None) // Skip past beginning of stream.
reader.ReadAndAssert();
while (reader.TokenType == JsonToken.Comment) // Skip past comments.
reader.ReadAndAssert();
return reader;
}
public static JsonReader ReadAndAssert(this JsonReader reader)
{
if (reader == null)
throw new ArgumentNullException();
if (!reader.Read())
throw new JsonReaderException("Unexpected end of JSON stream.");
return reader;
}
}
public static class TypeExtensions
{
public static IEnumerable<Type> BaseTypesAndSelf(this Type type)
{
while (type != null)
{
yield return type;
type = type.BaseType;
}
}
}
Example
然后如下注释您的类,使用JsonPropertyAttribute.ItemConverterParameters
指定内部项目转换器CustomConverter
:
public class Example
{
[JsonConverter(typeof(CustomConverter))]
public int ExampleInt { get; set; }
[JsonProperty(ItemConverterType = typeof(CustomConverter))]
public List<int> ExampleList { get; set; }
[JsonProperty(ItemConverterType = typeof(ListItemConverterDecorator),
ItemConverterParameters = new object [] { typeof(CustomConverter) })]
public Dictionary<string, List<int>> ExampleDictionary { get; set; }
}
现在你应该准备好了。演示小提琴在这里。