将字典<long,value =“”>序列化为BSON文档

时间:2015-09-08 05:24:03

标签: mongodb-.net-driver

我想将Dictionary<long, VALUE>序列化为跟随MongoDB中的JSON。

{
   "213" : {},
   "63624" : {},
   ...
}

除了DictionaryRepresentation

之外,我不想要其他DictionaryRepresentation.Document.Document

我使用的是MongoDB C#驱动程序(v2.0.1.27),将long类型密钥转换为string是不明智的,这会导致异常。

谢谢

2 个答案:

答案 0 :(得分:5)

您可以使用现有的序列化程序执行此操作,但需要进行少量配置。

假设以下课程:

public class C
{
    public int Id { get; set; }
    public Dictionary<long, long> D { get; set; }
}

您可以为D属性(Dictionary)配置自定义序列化程序,该序列化程序使用将longs序列化为字符串的键序列化程序。代码如下所示:

BsonClassMap.RegisterClassMap<C>(cm =>
{
    cm.AutoMap();
    var customDictionarySerializer = new DictionaryInterfaceImplementerSerializer<Dictionary<long, long>>(
        dictionaryRepresentation: DictionaryRepresentation.Document,
        keySerializer: new Int64Serializer(BsonType.String),
        valueSerializer: BsonSerializer.SerializerRegistry.GetSerializer<long>());
    cm.GetMemberMap(c => c.D).SetSerializer(customDictionarySerializer);
});

这里的关键思想是即使键和值都是长的,我们也会为键和值使用不同的序列化器。

如果我们再进行快速测试:

var document = new C { Id = 1, D = new Dictionary<long, long> { { 2, 3 } } };
var json = document.ToJson();
Console.WriteLine(json);

我们看到Dictionary键现在被序列化为字符串:

{ "_id" : 1, "D" : { "2" : NumberLong(3) } }

答案 1 :(得分:1)

我还制定了另一种解决方案,希望它可以帮助其他人

public class LongDictionarySerializer<K> : DictionarySerializerBase<Dictionary<long, K>>
{
    public LongDictionarySerializer() : base(DictionaryRepresentation.Document)
    {
    }

    protected override Dictionary<long, K> CreateInstance()
    {
        return new Dictionary<long, K>();
    }

    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, Dictionary<long, K> value)
    {
        if (value != null)
        {
            Dictionary<string, K> dic = value.ToDictionary(d => d.Key.ToString(), d => d.Value);
            BsonSerializer.Serialize<Dictionary<string, K>>(context.Writer, dic);
        }
        else
            BsonSerializer.Serialize<object>(context.Writer, null);
    }
    public override Dictionary<long, K> Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    {
        Dictionary<string, K> dic = BsonSerializer.Deserialize<Dictionary<string, K>>(context.Reader);
        if (dic == null)
            return null;

        Dictionary<long, K> ret = new Dictionary<long, K>();
        foreach( var pair in dic )
        {
            long key;
            if (!long.TryParse(pair.Key, out key))
                continue;
            ret[key] = pair.Value;
        }
        return ret;
    }
}

然后在现场

[BsonElement(Fields.Markets)]
[BsonSerializer(typeof(LongDictionarySerializer<XXX>))]
public Dictionary<long, XXX> Markets { get; set; }