在Json.NET中使用JsonSerializerSettings在属性中指定时如何禁用TypeNameHandling？

Ankush 发表于 Dev

安库什

有时"$type"，即使由指定，我也需要抑制Json.NET的属性输出JsonPropertyAttribute.ItemTypeNameHandling。如何才能做到这一点？

我的根类如下所示：

public class DomainResource
{
    [JsonProperty(ItemTypeNameHandling = TypeNameHandling.Auto)]
    public List<Extension> Extensions { get; set; }
}

此外，我还有一个如下的类层次结构Extension：

public class Extension
{
    readonly string url;

    public string Url { get { return url; } }

    public Extension(string url)
    {
        this.url = url;
    }
}

public class IntegerExtension : Extension
{
    public IntegerExtension(string url) : base(url) { }

    [JsonProperty("ValueInteger")]
    public int Value { get; set; }
}

我想ItemTypeNameHandling在序列化过程中的某些情况下忽略，但是我找不到解决方法。当我不想要"$type"使用以下代码的属性时，我尝试使用TypeNameHandling.None将JsonSerializerSettings设置为jsonconvert的输入：

public static string SerializeObject(object value)
{
    JsonSerializerSettings jsonSettings = new JsonSerializerSettings
    {
        ContractResolver = new CamelCasePropertyNamesContractResolver(),
        NullValueHandling = NullValueHandling.Ignore,
        TypeNameHandling = TypeNameHandling.None,

    };
    jsonSettings.Converters.Add(new StringEnumConverter
    {
        CamelCaseText = true
    });
    return JsonConvert.SerializeObject(value, Formatting.None, jsonSettings);
}

然后按如下方式使用它：

var res = new DomainResource();
res.Extensions = new List<Extension>();
res.Extensions.Add(new IntegerExtension("ewwer"){Value = 3});

var x = CustomJsonConvert.SerializeObject(res);

我想要的JSON是：

{“扩展名”：[{“ valueInteger”：3，“ url”：“ ewwer”}]}

但是，它包含"$type"如下所示的属性：

{“ extensions”：[{“ $ type”：“ DicomtoJsonConverter.IntegerExtension，DicomtoJsonConverter”，“ valueInteger”：3，“ url”：“ ewwer”}]}}

如何在不更改类的情况下抑制"$type"属性的输出？DomainResource

数据库

即使由或指定，您也可以使用自定义ContractResolver禁止显示类型信息。首先，定义以下合同解析器：JsonPropertyAttribute.TypeNameHandlingJsonPropertyAttribute.ItemTypeNameHandlingJsonContainerAttribute.ItemTypeNameHandling

public class NoTypeNameHandlingContractResolver : DefaultContractResolver
{
    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
    {
        var property = base.CreateProperty(member, memberSerialization);
        // Suppress JsonPropertyAttribute.TypeNameHandling
        property.TypeNameHandling = null;
        // Suppress JsonPropertyAttribute.ItemTypeNameHandling
        property.ItemTypeNameHandling = null;
        return property;
    }

    protected override JsonContract CreateContract(Type objectType)
    {
        var contract = base.CreateContract(objectType);
        if (contract is JsonContainerContract)
        {
            // Suppress JsonContainerAttribute.ItemTypeNameHandling
            ((JsonContainerContract)contract).ItemTypeNameHandling = null;
        }
        return contract;
    }
}

然后，修改CustomJsonConvert.SerializeObject()如下：

public static class CustomJsonConvert
{
    // You may want to cache the contract resolver for best performance, see
    // https://stackoverflow.com/questions/33557737/does-json-net-cache-types-serialization-information
    static readonly JsonSerializerSettings jsonSettings;
    static CustomJsonConvert()
    {
        jsonSettings = new JsonSerializerSettings
        {
            ContractResolver = new NoTypeNameHandlingContractResolver
            {
                NamingStrategy = new CamelCaseNamingStrategy
                {
                    // These are the settings used by CamelCasePropertyNamesContractResolver by default.
                    // Change them if this is not what you want.
                    OverrideSpecifiedNames = true,
                    ProcessDictionaryKeys = true,
                },
            },
            NullValueHandling = NullValueHandling.Ignore,
            TypeNameHandling = TypeNameHandling.None,
            Converters = { new StringEnumConverter { CamelCaseText = true } },
        };
    }

    public static string SerializeObject(object value)
    {
        return JsonConvert.SerializeObject(value, Formatting.None, jsonSettings);
    }
}

如果您使用的Json.NET版本早于9.0.1，则由于该版本中引入了Json.NET，因此您需要继承CamelCasePropertyNamesContractResolver而不是继承。DefaultContractResolverNamingStrategy