如何在反序列化时设置某些属性的值？

Question

我有一个 class，其属性设置器依赖于VeryImportantProperty 。 但是该属性不应按设计序列化。

因此，当我收到 JSON 时，我必须在反序列化期间和设置其他属性之前设置VeryImportantProperty 。

我想这可以通过修改ContractResolver来完成。 我在那里存储了VeryImportantProperty的值，但我不知道如何分配它

我尝试使用以下ContractResolver ，但它不影响

public class MyContractResolver : DefaultContractResolver
{
    public VeryImportantClass VeryImportantPropertyValue { get; set; }
        
    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
    {
        var property = base.CreateProperty(member, memberSerialization);
            
        if (property.PropertyName == "VeryImportantProperty" && VeryImportantPropertyValue != null)
        {
            property.DefaultValue = VeryImportantPropertyValue;
            property.DefaultValueHandling = DefaultValueHandling.Populate;
            property.Order = -1;
        }

        return property;
    }
}

Answer 1

我通过创建覆盖CreateContract的ContractResolver来解决这个问题，将Converter设置为覆盖Create的自定义转换器以将我的VeryImportantProperty传递给构造函数

代码：

public class MyContractResolver : DefaultContractResolver
{
    public VeryImportantClass VeryImportantPropertyValue { get; set; }

    protected override JsonContract CreateContract(Type objectType)
    {
        var contract = base.CreateContract(objectType);
        if (VeryImportantPropertyValue == null)
            return contract;

        // Solution for multiple classes is commented
        if (objectType == typeof(ContainerClass)/* || objectType.IsSubclassOf(typeof(BaseContainer))*/)
        {
            contract.Converter = new ImportantClassConverter(VeryImportantPropertyValue);
        }
        return contract;
    }

    private class ImportantClassConverter: CustomCreationConverter<VeryImportantClass>
    {
        public EntityConverter(VeryImportantClass veryImportantPropertyValue)
        {
            _veryImportantPropertyValue= veryImportantPropertyValue;
        }

        private readonly VeryImportantClass _veryImportantPropertyValue;

        public override VeryImportantClass Create(Type objectType)
        {
            // Might be simplified but it was used for multiple container classes with one parent
            return objectType.GetConstructor(new[] { typeof(ContainerClass) })
                ?.Invoke(new[] { _veryImportantPropertyValue }) as ContainerClass;
        }
    }
}