C＃MongoDB收集数量并从Asqueryable中查找文档结果

Question

在我的c＃console应用程序项目中，我使用的是mongodb.2.4.3，连接到mongodb 3.2.10。

如何计算文档数量，从已过滤查询中找到第一个和最后一个文档？

    static void Main(string[] args)
    {
        DateTime myTimeConvert = DateTime.Now;
        var client = new MongoClient("mongodb://localhost:27017");
        var DB = client.GetDatabase("football");
        var players = DB.GetCollection<Player>("players");

        var playersInBrazil = players.AsQueryable()
                         .Where(p => p.country == "Brazil");
        //count the number of documents and find the first and the last document from the filtered query 
    }
    internal class Player
    {
        public ObjectId Id { get; set; }
        public string firstname { get; set; }
        public BsonDateTime birthdate { get; set; }
        public string country { get; set; }
        public double goals { get; set; }
    }

}

Answer 1

var countPlayersInBrazil = players.AsQueryable().Count(p => p.country == "Brazil");
var firstPlayersInBrazil = players.AsQueryable().First(p => p.country == "Brazil");
var lastPlayersInBrazil = players.AsQueryable().Last(p => p.country == "Brazil");