c# - 如何让 Json Serialize 忽略字典键

Question

我正在尝试序列化一个类中的字典，并且 CustomAttributes 字典中的键正在格式化，即使我提供的 ProcessDictionaryKeys 参数为 false。

我添加了 [JsonProperty]，如下所示:

[JsonProperty(NamingStrategyType = typeof(SnakeCaseNamingStrategy), NamingStrategyParameters = new object[] { false, false })]
public IDictionary<string, string> CustomAttributes { get; set; }

我的 CustomAttributes 数据如下所示:

CustomAttributes = new Dictionary<string, string>()
{
    {"Custom Attribute 1", "1"},
    {"CustomAttribute 2", "2"}
}

生成的 JSON 如下所示:

custom_attributes\":{\"custom Attribute 1\":\"1\",\"customAttribute 2\":\"2\"

如您所见，每个字典键的首字母都未大写。我怎样才能阻止这种情况发生？

编辑:将 ProcessDictionaryKeys 参数更改为 true 似乎没有任何区别。

Answer 1

如 demo fiddle #1 here 所示，仅使用问题中的代码不会重现问题。 .

相反，您必须使用一些全局序列化程序设置进行序列化 JsonSerializerSettings.ContractResolver.NamingStrategy.ProcessDictionaryKeys = true 例如 CamelCasePropertyNamesContractResolver :

var settings = new JsonSerializerSettings
{
    ContractResolver = new CamelCasePropertyNamesContractResolver(),
};
var json = JsonConvert.SerializeObject(root, Formatting.Indented, settings);

演示 fiddle #2 here .

假设这是正确的，[JsonProperty(NamingStrategyType = typeof(SnakeCaseNamingStrategy), NamingStrategyParameters = new object[] { false, false })] 的原因不会导致字典键被逐字序列化的是 JsonPropertyAttribute.NamingStrategyType 仅适用于属性名称本身(此处为 CustomAttributes)，不适用于属性项目 的属性名称。如果您想对属性的项目应用命名策略，您需要像 ItemNamingStrategyType 这样的东西-- 但是 JsonPropertyAttribute 没有这样的功能。

那么，您有哪些选择？

1. 您可以修改全局命名策略以逐字序列化字典名称，如 Keep casing when serializing dictionaries 所示。 。

2. 你可以继承Dictionary<TKey, TValue>并申请 [JsonDictionary(NamingStrategyType = typeof(DefaultNamingStrategy))] 如 this answer 所示给 Applying JsonDictionary attribute to dictionary :

   [JsonDictionary(NamingStrategyType = typeof(DefaultNamingStrategy))]
   public class VerbatimDictionary<TKey, TValue> : Dictionary<TKey, TValue>
   {
   }
   

   然后:

   CustomAttributes = new VerbatimDictionary<string, string>()
   {
       {"Custom Attribute 1", "1"},
       {"CustomAttribute 2", "2"}
   }
   

   演示 fiddle #3 here .

3. 你可以介绍一个 custom JsonConverter 序列化 IDictionary<TKey, TValue>使用默认的命名策略。首先，定义以下转换器:

   public class VerbatimDictionaryConverter<TKey, TValue> : JsonConverter<IDictionary<TKey, TValue>>
   {
       [JsonDictionary(NamingStrategyType = typeof(DefaultNamingStrategy))]
       class VerbatimDictionarySerializationSurrogate : IReadOnlyDictionary<TKey, TValue>
       {
           readonly IDictionary<TKey, TValue> dictionary;
   
           public VerbatimDictionarySerializationSurrogate(IDictionary<TKey, TValue> dictionary) 
           { 
               if (dictionary == null) 
                   throw new ArgumentNullException(nameof(dictionary));
               this.dictionary = dictionary; 
           }
           public bool ContainsKey(TKey key) { return dictionary.ContainsKey(key); }
           public bool TryGetValue(TKey key, out TValue value) { return dictionary.TryGetValue(key, out value); }
           public TValue this[TKey key] { get { return dictionary[key]; } }
           public IEnumerable<TKey> Keys { get { return dictionary.Keys; } }
           public IEnumerable<TValue> Values { get { return dictionary.Values; } }
           public int Count { get { return dictionary.Count; } }
           public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator() { return dictionary.GetEnumerator(); }
           IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); }
       }
   
       public override void WriteJson(JsonWriter writer, IDictionary<TKey, TValue> value, JsonSerializer serializer)
       {
           serializer.Serialize(writer, new VerbatimDictionarySerializationSurrogate(value));
       }
   
       public override bool CanRead { get { return false; } }
   
       public override IDictionary<TKey, TValue> ReadJson(JsonReader reader, Type objectType, IDictionary<TKey, TValue> existingValue, bool hasExistingValue, JsonSerializer serializer) { throw new NotImplementedException(); }
   }
   

   并按如下方式应用:

   [JsonConverter(typeof(VerbatimDictionaryConverter<string, string>))]
   public IDictionary<string, string> CustomAttributes { get; set; }       
   

   演示 fiddle #4 here .