小编典典

如何将包含具有固定模式的值数组的对象反序列化为强类型数据类?

c#

我在寻找一种干净的(尽可能)的方式来反序列化某些特定格式的JSON数据时遇到了一些麻烦。我想将数据反序列化为强类型数据对象类,这在细节方面非常灵活。这是数据的示例:

{
    "timestamp": 1473730993,
    "total_players": 945,
    "max_score": 8961474,
    "players": {
            "Player1Username": [
            121,
            "somestring",
            679900,
            5,
            4497,
            "anotherString",
            "thirdString",
            "fourthString",
            123,
            22,
            "YetAnotherString"],
        "Player2Username": [
            886,
            "stillAstring",
            1677,
            1,
            9876,
            "alwaysAstring",
            "thirdString",
            "fourthString",
            876,
            77,
            "string"]
        }
}

我不确定的具体部分是:

  1. 玩家集合会被视为字典吗?用户名可以用作键,但是值让我失望,因为它是字符串和整数值的混合集合。
  2. 玩家完全由未命名的值组成。我几乎总是使用已命名属性和值(例如,时间戳,total_players等)的JSON数据。

说我有一个像这样的顶级课程:

public class ScoreboardResults
{
    public int timestamp { get; set; }
    public int total_players { get; set; }
    public int max_score { get; set; }
    public List<Player> players { get; set; }
}

考虑到它基本上是一个键/值,而用户名是键,并且该值是混合整数和字符串的集合,Player对象会是什么样?每个玩家元素的数据始终是相同的顺序,因此我知道集合中的第一个值是它们的UniqueID,第二个值是玩家说明,等等。我希望玩家类是这样的:

public class Player
{
    public string Username { get; set; }
    public int UniqueID { get; set; }
    public string PlayerDescription { get; set; }
    ....
    ....
    .... Following this pattern for all of the values in each player element
    ....
    ....
}

我确信这是使用JSON.NET要做的一件非常简单的事情,这就是为什么我想要避免我对实现此想法有任何想法的原因。我想出的东西在序列化过程中可能很不雅致,并且可能在一定程度上容易出错。

编辑

这是snow_FFFFFF建议将过去用作JSON类时生成的类:

public class Rootobject
{
    public int timestamp { get; set; }
    public int total_players { get; set; }
    public int max_score { get; set; }
    public Players players { get; set; }
}

public class Players
{
    public object[] Player1Username { get; set; }
    public object[] Player2Username { get; set; }
}

对我来说不清楚的是如何将“
players”元素中的JSON数据反序列化为List,而Player1Username是Player对象上的简单字符串属性。至于混合的字符串和整数的集合,我相信我可以毫无问题地将它们放入Player对象的各个属性中。


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2020-05-19

共1个答案

小编典典

Visual Basic
.NET中的反序列化JSON进行
转换的转换应该执行您所需的操作,并将其适当地从VB.NET转换为c#:

public class ObjectToArrayConverter<T> : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return typeof(T) == objectType;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        var objectType = value.GetType();
        var contract = serializer.ContractResolver.ResolveContract(objectType) as JsonObjectContract;
        if (contract == null)
            throw new JsonSerializationException(string.Format("invalid type {0}.", objectType.FullName));
        writer.WriteStartArray();
        foreach (var property in SerializableProperties(contract))
        {
            var propertyValue = property.ValueProvider.GetValue(value);
            if (property.Converter != null && property.Converter.CanWrite)
                property.Converter.WriteJson(writer, propertyValue, serializer);
            else
                serializer.Serialize(writer, propertyValue);
        }
        writer.WriteEndArray();
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        var contract = serializer.ContractResolver.ResolveContract(objectType) as JsonObjectContract;
        if (contract == null)
            throw new JsonSerializationException(string.Format("invalid type {0}.", objectType.FullName));

        if (reader.MoveToContentAndAssert().TokenType == JsonToken.Null)
            return null;
        if (reader.TokenType != JsonToken.StartArray)
            throw new JsonSerializationException(string.Format("token {0} was not JsonToken.StartArray", reader.TokenType));

        // Not implemented: JsonObjectContract.CreatorParameters, serialization callbacks, 
        existingValue = existingValue ?? contract.DefaultCreator();

        using (var enumerator = SerializableProperties(contract).GetEnumerator())
        {
            while (true)
            {
                switch (reader.ReadToContentAndAssert().TokenType)
                {
                    case JsonToken.EndArray:
                        return existingValue;

                    default:
                        if (!enumerator.MoveNext())
                        {
                            reader.Skip();
                            break;
                        }
                        var property = enumerator.Current;
                        object propertyValue;
                        // TODO:
                        // https://www.newtonsoft.com/json/help/html/Properties_T_Newtonsoft_Json_Serialization_JsonProperty.htm
                        // JsonProperty.ItemConverter, ItemIsReference, ItemReferenceLoopHandling, ItemTypeNameHandling, DefaultValue, DefaultValueHandling, ReferenceLoopHandling, Required, TypeNameHandling, ...
                        if (property.Converter != null && property.Converter.CanRead)
                            propertyValue = property.Converter.ReadJson(reader, property.PropertyType, property.ValueProvider.GetValue(existingValue), serializer);
                        else
                            propertyValue = serializer.Deserialize(reader, property.PropertyType);
                        property.ValueProvider.SetValue(existingValue, propertyValue);
                        break;
                }
            }
        }
    }

    static IEnumerable<JsonProperty> SerializableProperties(JsonObjectContract contract)
    {
        return contract.Properties.Where(p => !p.Ignored && p.Readable && p.Writable);
    }
}

public static partial class JsonExtensions
{
    public static JsonReader ReadToContentAndAssert(this JsonReader reader)
    {
        return reader.ReadAndAssert().MoveToContentAndAssert();
    }

    public static JsonReader MoveToContentAndAssert(this JsonReader reader)
    {
        if (reader == null)
            throw new ArgumentNullException();
        if (reader.TokenType == JsonToken.None)       // Skip past beginning of stream.
            reader.ReadAndAssert();
        while (reader.TokenType == JsonToken.Comment) // Skip past comments.
            reader.ReadAndAssert();
        return reader;
    }

    public static JsonReader ReadAndAssert(this JsonReader reader)
    {
        if (reader == null)
            throw new ArgumentNullException();
        if (!reader.Read())
            throw new JsonReaderException("Unexpected end of JSON stream.");
        return reader;
    }
}

接下来,将转换器添加到您的Player类中,并使用指示每个属性的顺序JsonPropertyAttribute.Order

[JsonConverter(typeof(ObjectToArrayConverter<Player>))]
public class Player
{
    [JsonProperty(Order = 1)]
    public int UniqueID { get; set; }
    [JsonProperty(Order = 2)]
    public string PlayerDescription { get; set; }
    // Other fields as required.
}

最后,按如下所示声明您的根对象:

public class ScoreboardResults
{
    public int timestamp { get; set; }
    public int total_players { get; set; }
    public int max_score { get; set; }
    public Dictionary<string, Player> players { get; set; }
}

请注意,作为键,我已经Username离开Player班级进入字典。

演示在这里这里摆弄。

2020-05-19