協定世界時と現地の日時をMongoに保存する

これは、MongoDBに生の値を保存させ、DateTimeオブジェクトのDateTimeKind属性を無視する方法です。

これはお客様のビジネスロジックには当てはまらない場合がありますが、特定の理由から私たちにとっては理にかなっています。

BsonSerializer.RegisterSerializer(typeof(DateTime), new MyMongoDBDateTimeSerializer());


public class MyMongoDBDateTimeSerializer : DateTimeSerializer
{
    //  MongoDB returns datetime as DateTimeKind.Utc, which cann't be used in our timezone conversion logic
    //  We overwrite it to be DateTimeKind.Unspecified
    public override object Deserialize(MongoDB.Bson.IO.BsonReader bsonReader, System.Type nominalType, MongoDB.Bson.Serialization.IBsonSerializationOptions options)
    {
        var obj = base.Deserialize(bsonReader, nominalType, options);
        var dt = (DateTime) obj;
        return new DateTime(dt.Ticks, DateTimeKind.Unspecified);
    }

    //  MongoDB returns datetime as DateTimeKind.Utc, which cann't be used in our timezone conversion logic
    //  We overwrite it to be DateTimeKind.Unspecified
    public override object Deserialize(MongoDB.Bson.IO.BsonReader bsonReader, Type nominalType, Type actualType, MongoDB.Bson.Serialization.IBsonSerializationOptions options)
    {
        var obj = base.Deserialize(bsonReader, nominalType, actualType, options);
        var dt = (DateTime)obj;
        return new DateTime(dt.Ticks, DateTimeKind.Unspecified);
    }

    //  MongoDB stores all datetime as Utc, any datetime value DateTimeKind is not DateTimeKind.Utc, will be converted to Utc first
    //  We overwrite it to be DateTimeKind.Utc, becasue we want to preserve the raw value
    public override void Serialize(MongoDB.Bson.IO.BsonWriter bsonWriter, System.Type nominalType, object value, MongoDB.Bson.Serialization.IBsonSerializationOptions options)
    {
        var dt = (DateTime) value;
        var utcValue = new DateTime(dt.Ticks, DateTimeKind.Utc);
        base.Serialize(bsonWriter, nominalType, utcValue, options);
    }
}