使用C＃驱动程序查询mongodb无法正常工作

Question

从互联网上粘贴示例以查询我们的mongodb并查找字段时出现以下错误。

我看不出我做错了什么，如果我不能很快解决，我会回到SQL :(

我只想说能找到带3扇门的汽车。

感谢您的帮助！非常感谢。

连接代码

public MongoDatabase GetDatabase
{
    get
    {
        MongoClient mc = new MongoClient();
        var server = mc.GetServer();
        return server.GetDatabase("players");
    }
 }

代码示例

var numberOfDoors = 3;

var collection = GetDatabase.GetCollection<CarCollection>("Cars");

// Have tried using my Car object instead of BsonDocument but little difference
var filter = Builders<BsonDocument>.Filter.Eq("NumberOfDoors", numberOfDoors);

var result = collection.Find(filter);

错误消息

Argument 1: cannot convert from 'MongoDB.Driver.FilterDefinition<MongoDB.Bson.BsonDocument>' to 'MongoDB.Driver.IMongoQuery'

文档结构

{
    "_id" : ObjectId("..."),
    "Members" : [ 
        {
            "EmailAddress" : "",
            ...
        }, 
        {
            "EmailAddress" : "",
            ...
        }, 
        {
            "EmailAddress" : "",
            ...
        }
    ]
}

C＃结构

public class MemberCollection
{
    public ObjectId _id { get; set; }

    public MemberEntity[] Members { get; set; }
}

public class MemberEntity
{
    public int _id { get; set; }

    public string Password { get; set; }

    public string EmailAddress { get; set; }
}

更新 - 显示错误消息

文档结构

更新＃2

更新3

Answer 1

您错误地使用了Builders<CarCollection>.Filter.Eq()：

var numberOfDoors = 3;

var collection = ..GetCollection<CarCollection>("Cars");

var builder = Builders<CarCollection>.Filter;
var filt = builder.Where(car => car.NumberOfDoors == numberOfDoors);
var list = await collection.Find(filt).ToListAsync();

这假定：

public class CarCollection : IEnumerable<Car> { ... }

和

public class Car { public int NumberOfDoors { get; set; } ... }

Answer 2

您的以下行错误

Builders<BsonDocument>.Filter.Eq("NumberOfDoors", numberOfDoors);

它应该在下面，因为您尝试在CarCollection上放置过滤器。这是错误的根源。

Builders<CarCollection>.Filter.Eq("NumberOfDoors", numberOfDoors);

根据您最近的编辑，您应该将过滤器定义更改为下面，因为您实际上是尝试在member个对象的嵌套数组上放置过滤器

var filter = Builders<MemberCollection>.Filter.Eq("Members.EmailAddress", emailAddress);

等效的MongoDB查询将是

db.Getcollection('Members').Find({"Members.EmailAddress": "test@msn.com"})

修改

不确定你的结局有什么不对，但试试如下

var collection = _mongoclientProvider.GetDatabase.GetCollection<MemberCollection>("Members");
Expression<Func<MemberCollection, bool>> expression = mc => mc.Members.Any(m => m.EmailAddress == emailAddress);
var list = collection.Find(expression).ToList();