将位置坐标的Mongo BSON数组反序列化为自定义C＃类

Question

I have a document stored in Mongo of the below format:

"address" : {
    "building" : "469",
    "coord" : [ 
        -73.961704, 
        40.662942
    ],
    "street" : "Flatbush Avenue",
    "zipcode" : "11225"
}

I am using the official C# Mongo Driver to communicate with The MongoDB instance. I have defined the following POCO classes to correspond to the document:

public class Coordinate
{
    public float Lat { get; set; }
    public float Long { get; set; }
}

public class Address
{
    [BsonElement("street")]
    public string Street { get; set; }
    [BsonElement("zipcode")]
    public string ZipCode { get; set; }
    [BsonElement("building")]
    public string Building { get; set; }
    [BsonElement("coord")]
    public Coordinate Coord { get; set; }
}

But I am not certain what has to be done in terms of the serialization attributes so that the coord BSON array values are deserialized into the Coordinate class that I have created.

Any ideas?

Answer 1

You need to create a custom serializer :

public class MyCustomArraySerializer : SerializerBase<Coordinate>
{
    public override Coordinate Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    {
        context.Reader.ReadStartArray();
        var lat=context.Reader.ReadDouble();
        var lon = context.Reader.ReadDouble();
        context.Reader.ReadEndArray();

        return new Coordinate() { Long = (float)lon, Lat = (float)lat };
    }
    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, Coordinate value)
    {
        context.Writer.WriteStartArray();
        context.Writer.WriteDouble(value.Lat);
        context.Writer.WriteDouble(value.Long);
        context.Writer.WriteEndArray();
    }
}

And then add this attribute on Coord property:

public class Address
{
    //...
    //Add this attribute
    [BsonSerializer(typeof(MyCustomArraySerializer))]
    public Coordinate Coord { get; set; }
}