Question

我想在MongoDB中序列化，成员Engines（枚举的HashSet）作为字符串，将名称视为字符串，而不是数字课程是：

public class EnginesPerFile
{
    public Guid FileId { get; set; }
    public string Path { get; set; }
    public HashSet<EngineType> Engines { get; set; }
}

我想这样映射：

BsonClassMap.RegisterClassMap<EnginesPerFile>(cm =>
            {
                cm.AutoMap();
                cm.MapIdField(c => c.FileId);
                cm.MapMember(c => c.Engines).SetSerializer(new EnumSerializer<EngineType>(BsonType.String));
            });

但是我收到了一个错误：

Value type of serializer is EngineType and does not match member type System.Collections.Generic.HashSet`1[[Playground.Model.EngineType, Model, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].

参数名称：serializer。

如何在MongoDB中序列化枚举的hashset？

Answer 1

我通过编写自定义Serializer来修复它:( EngineType可以是通用T）

 public class MyHashSetSerializer : SerializerBase<HashSet<EngineType>>
{
    private readonly IBsonSerializer _serializer =
        BsonSerializer.LookupSerializer(typeof(EngineType));

    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, HashSet<EngineType> value)
    {
        var set = (HashSet<EngineType>)value;

        context.Writer.WriteStartDocument();           
        int i = 0;
        foreach (var element in set)
        {

            context.Writer.WriteName($"[{i}]");
            context.Writer.WriteString(element.ToString());
        }
        context.Writer.WriteEndDocument();
    }

    public override HashSet<EngineType> Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    {
        var set = new HashSet<EngineType>();

        context.Reader.ReadStartDocument();
        while (context.Reader.ReadBsonType() != 0)
        {
            context.Reader.SkipName();
            var element =
                (EngineType)_serializer.Deserialize(context, args);              
            set.Add(element);
        }
        context.Reader.ReadEndDocument();

        return set;
    }
}

然后我像这样注册类地图：

BsonClassMap.RegisterClassMap<EnginesPerFile>(cm =>
            {
                cm.AutoMap();
                cm.MapIdField(c => c.FileId);
                cm.MapMember(c => c.Engines).SetSerializer(new MyHashSetSerializer());
            });

在MongoDB中序列化枚举的Hashset

1 个答案: