使用C#LINQ驱动程序比较Mongodb中的日期 [英] Comparing dates in Mongodb with C# LINQ driver

问题描述

我有一个 MongoDB 集合，其中包含一个表示日期的字符串字段.在我的C#应用​​程序中，我将结果映射到带有聚合字段的类，该字段将该字符串转换为DateTime对象

I have a MongoDB collection with a string field representing a date. In my C# app I map the results to a class with an aggregate field that convert that string to a DateTime object

[BsonIgnoreExtraElements]
public class Tweet
{
    public ObjectId Id { get; set; }

    [BsonElement("text")]
    public string Texto { get; set; }

    [BsonElement("created_at")]
    public string Fecha { get; set; }

    public DateTime FechaConvertida
    {
        get
        {
            var formato = "ddd MMM dd HH:mm:ss zzzz yyyy"; //'Sun Oct 23 19:42:04 +0000 2016'
            var enUS = new CultureInfo("en-US");
            var fechaConvertida = DateTime.ParseExact(this.Fecha, formato, enUS, DateTimeStyles.None);
            return fechaConvertida;
        }
    }
}

然后在我的api上进行查询以过滤两个日期之间的元素(使用"CSharp驱动程序LINQ")

Then on my api I make a query filtering elements between two dates (using 'CSharp Driver LINQ')

public IEnumerable<Tweet> GetTweetsDePeriodo(string nombreColeccion, int dias)
    {
        var hoy = DateTime.Today;
        var fechaInicial = hoy.AddDays(-dias);

        var coleccion = _db.GetCollection<Tweet>(nombreColeccion).AsQueryable<Tweet>();
        var tweetsFiltrados = (from c in coleccion
                               where c.FechaConvertida >= fechaInicial
                               select c
                               ).ToList();
        return coleccion;
    }

然后出现以下错误: *处理请求时发生未处理的异常.InvalidOperationException:{document}.不支持FechaConvertida

有什么主意吗?预先感谢，

Any idea? Thanks in advance,

推荐答案

最后，我找到了一种针对日期字段使用自定义序列化程序的解决方案.看起来就是这样.

Finally I've found a solution using a custom serializer for the Date field. This is how it looks like.

我的课:

[BsonIgnoreExtraElements]
public class Tweet
{
    public ObjectId Id { get; set; }

    [BsonElement("text")]
    public string Texto { get; set; }

    [BsonElement("created_at")]
    [BsonSerializer(typeof(FechaTweetsSerializer))]
    public DateTime Fecha { get; set; }
}

还有我的自定义序列化器:

And my custom serializer:

public class FechaTweetsSerializer : SerializerBase<DateTime>
{

    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, DateTime value)
    {
        context.Writer.WriteString(value.ToString(CultureInfo.InvariantCulture));
    }

    public override DateTime Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    {
        var fecha = context.Reader.ReadString();
        return ConvertirFecha(fecha);
    }

    private DateTime ConvertirFecha(string fechaFormatoTwitter)
    {
        var formato = "ddd MMM dd HH:mm:ss zzzz yyyy"; //'Sun Oct 23 19:42:04 +0000 2016'
        var enUS = new CultureInfo("en-US");
        var fechaConvertida = DateTime.ParseExact(fechaFormatoTwitter, formato, enUS, DateTimeStyles.None);
        return fechaConvertida;
    }
}

希望它对某人有帮助.

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