C# JSON.NET自定义构造函数

作为这个问题的一个部分问题，我试图在反序列化期间调用自定义构造函数。我的简化类层次结构如下所示：

public abstract class BusinessObjectBase
{
    internal BusinessObjectBase(SerializationContext context)
        : base(context)
    {
    }
}

public abstract class EditableObjectBase : BusinessObjectBase
{
    protected EditableObjectBase(SerializationContext context)
        : base(context)
    {
    }
}

public class EditableObjectCollection<TObject> : BusinessObjectBase, ICollection<TObject>, IList, INotifyCollectionChanged where TObject : BusinessObjectBase
{
    protected EditableObjectCollection(SerializationContext context)
        : base(context)
    {
    }
}

internal class BusinessObjectCreationConverter : JsonConverter
{
    public override bool CanWrite
    {
        get
        {
            return false;
        }
    }

    public override bool CanConvert(Type objectType)
    {
        return typeof(BusinessObjectBase).IsAssignableFrom(objectType);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        object result = null;

        if (reader.TokenType != JsonToken.Null)
        {
            JObject jsonObject = JObject.Load(reader);
            result = this.Create(objectType, jsonObject);
            Verification.Assert<NullReferenceException>(result != null, "No Business Object created.");
            serializer.Populate(jsonObject.CreateReader(), result);
        }

        return result;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
    }

    public BusinessObjectBase Create(Type objectType, JObject jsonObject)
    {
        JToken token       = jsonObject.SelectToken("$type");
        var typeString     = token.Value<string>();
        Type type          = Type.GetType(typeString);
        var businessObject = type.CreateUsingDesrializationConstructor<BusinessObjectBase>();

        businessObject.Initialize(true);
        return businessObject;
    }
}

如果我用集合初始化我的类

var collection = new EditableObjectCollection<TestEditableObject>(null);
var poco = new AnyPocoContainingBusinessObject { BusinessObject = collection };

我得到一个例外： 无法将JSON对象填充到类型“KS.Interfaces.Core.Entities.EditableObjectCollection`1[KS.Interfaces.Core.Entities.Tests.Unit.EditableObjectCollectionTests+TestEditableObject]”上。路径“$type”，第1行，位置47

在我的转换器的此代码行中：

serializer.Populate(jsonObject.CreateReader(), result);

有人能告诉我原因吗？我非常确定我创建了正确的类型，并且使用EditableObjectBase派生对象，一切都很好。只有收藏似乎不起作用

如有任何提示，我们将不胜感激

---

Carsten

即使我还没有找到让转换器工作的方法，但在调试问题的过程中我学到了一件事：

转换器似乎应该返回仍然具有相同JsonToken值的对象。在我的例子中，原始对象的JsonToken是JsonToken.object，但是对于我的转换结果，正确的标记值应该是JsonToken.Array，但是读者仍然可以看到JsonToken.object。在这一点上，我停止了我的研究，因为我找到了一种更好的方法来调用我的自定义构造函数

我编写了自己的合同解析器：

   internal class BusinessBaseContractResolver : DefaultContractResolver
   {
        public BusinessBaseContractResolver()
        {
            this.DefaultMembersSearchFlags |= BindingFlags.NonPublic;    
        }

        public override JsonContract ResolveContract(Type type)
        {
            JsonContract contract = base.ResolveContract(type);
            if (typeof(BusinessObjectBase).IsAssignableFrom(type))
            {
                contract.DefaultCreator = delegate
                {
                    var businessObject = type.CreateUsingDeserializationConstructor<BusinessObjectBase>();
                    businessObject.Initialize(true);

                    return businessObject;
                };
            }

            return contract;
        }
    }

内部类BusinessBaseContractResolver:DefaultContractResolver
{
public BusinessBaseContractResolver（）
{
this.DefaultMembersSearchFlags |=BindingFlags.NonPublic；
}
公共重写JsonContract ResolveContract（类型）
{
JsonContract contract=base.ResolveContract（类型）；
if（typeof（BusinessObjectBase）.IsAssignableFrom（type））
{
contract.DefaultCreator=委托
{
var businessObject=type.CreateUsingDeserializationConstructor（）；
businessObject.Initialize（true）；
返回业务对象；
};
}
退货合同；
}
}

我希望这对某人有帮助

致以最良好的祝愿， 卡斯滕

serializer.Populate(jsonObject.CreateReader(), result);

   internal class BusinessBaseContractResolver : DefaultContractResolver
   {
        public BusinessBaseContractResolver()
        {
            this.DefaultMembersSearchFlags |= BindingFlags.NonPublic;    
        }

        public override JsonContract ResolveContract(Type type)
        {
            JsonContract contract = base.ResolveContract(type);
            if (typeof(BusinessObjectBase).IsAssignableFrom(type))
            {
                contract.DefaultCreator = delegate
                {
                    var businessObject = type.CreateUsingDeserializationConstructor<BusinessObjectBase>();
                    businessObject.Initialize(true);

                    return businessObject;
                };
            }

            return contract;
        }
    }