使用Newtonsoft.Json進行類型轉換

Question

以前，我使用IDataContractSurrogate來序列化我的數據，但它與CPL（便攜式類庫）不兼容，所以我現在使用Newtonsoft。

但是，我必須將ObservableCollection類型轉換為List：

myobj [ { id:1, name="test1", value="test_1"}, { id:2, name="test2", value="test_2"}]

到myobj ["test1", "test2"],

可能嗎 ？ 我這樣嘗試過：

public class ccrUser : DefaultContractResolver { // Newtonsoft.Json.Serialization.IContractResolver

        private bool toSerialise;
        public static readonly ccrUser Instance = new ccrUser(true);

        /// <summary>Constructeur</summary>
        /// <param name="pToSerialise">Indique le sens qui sera utlisé (les API ne donnent pas le même format en GET qu'elles attendent en POST).</param>
        public ccrUser(bool pToSerialise) : base() { toSerialise = pToSerialise; }

        protected override JsonContract CreateContract(Type objectType) {
            var contract = base.CreateContract(objectType);
            if ((toSerialise) && (objectType == typeof(ObservableCollection<tblGroup>))) {
                //contract.Converter = new Newtonsoft.Json.Converters.CustomCreationConverter<string>();
                return base.CreateArrayContract(objectType);
            } else
                return contract;
        }
        protected override List<MemberInfo> GetSerializableMembers(Type objectType) {
            var defaultMembers = base.GetSerializableMembers(objectType);
            if ((toSerialise) && (objectType == typeof(ObservableCollection<tblGroup>))) {
                return defaultMembers;
            } else
                return defaultMembers;
        }


        protected override JsonConverter ResolveContractConverter(Type objectType) {
            if (objectType == typeof(ObservableCollection<tblGroup>)) {
                return null; // pretend converter is not specified
            }
            return base.ResolveContractConverter(objectType);
        }

        /// <summary>JSON value provider that always returns a static value</summary>
        public class StaticValueProvider : IValueProvider {
            private readonly object _staticValue;
            public StaticValueProvider(object staticValue) {  _staticValue = staticValue; }
            public void SetValue(object target, object value) { throw new NotSupportedException(); }
            public object GetValue(object target) { return _staticValue; }
        }

        protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization) {
            JsonProperty property = base.CreateProperty(member, memberSerialization);
            if ((toSerialise) && (property.PropertyType == typeof(ObservableCollection<tblGroup>))) {
            }
            return property;
        }
    }

但找不到解決方案。

問候

Answer 1

您可以序列化/反序列化另一個屬性（另一種類型），而不是在序列化/反序列化過程本身進行轉換時：

// serialize only marked members
[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
public class SerializableObject
{
    // original property: not serialized
    public TypeA PropertyA { get; set; }

    [JsonProperty(nameof(PropertyA))]
    public TypeB PropertyB
    {
        get
        {
            // convert PropertyA value to TypeB
            return (TypeB)PropertyA;
        }
        set
        {
            // convert TypeB to TypeA and set PropertyA value
            PropertyA = (TypeA)value;
        }
    }
}

PropertyB （如果願意，可以是private ）僅用於序列化/反序列化PropertyA值作為另一種類型。

Answer 2

出現編譯錯誤，它無法將List <string>解析為IEnumerable <tblGroup>：

    [DataMember(Name ="groups")] 
public List<string> groupsApi { get { return (from c in (ObservableCollection<tblGroup>)_groups select c.value).ToList(); } set { _groups = new ObservableCollection<tblGroup>(value); } } 
public ObservableCollection<tblGroup> groups { get { return _groups; } set { _groups = value; } }