c#mongodb使用生成器查找派生对象

我有两个集合，它们存储从同一对象继承的两个不同对象（每个对象表示一个对象）

比如：

public abstract class BaseClass
{
    public string name = "someName";
}

public class FirstClass : BaseClass { ... }
public class SecondClass : BaseClass { ... }

var FirstCollection = mongo.GetCollection<FirstClass>("First");
var SecondClass =    mongo.GetCollection<SecondClass>("Second");

var filter = Builders<BaseClass>.Filter.Where(y => y.name == "someName");
var result = FirstCollection.Find(filter);

公共抽象类基类
{
公共字符串name=“someName”；
}
公共类第一类：基类{…}
公共类第二类：基类{…}
var FirstCollection=mongo.GetCollection（“第一”）；
var SecondClass=mongo.GetCollection（“第二”）；

现在，我有一个查询要在这两个集合上运行，只使用公共字段。 我想使用相同的查询，使用“MongoDB.Driver.Builders”

比如：

public abstract class BaseClass
{
    public string name = "someName";
}

public class FirstClass : BaseClass { ... }
public class SecondClass : BaseClass { ... }

var FirstCollection = mongo.GetCollection<FirstClass>("First");
var SecondClass =    mongo.GetCollection<SecondClass>("Second");

var filter = Builders<BaseClass>.Filter.Where(y => y.name == "someName");
var result = FirstCollection.Find(filter);

var-filter=Builders.filter.Where（y=>y.name==“someName”）；
var result=FirstCollection.Find（过滤器）；

---

你知道怎么做吗？

通过下面的设置，你可以做的和你已经做的差不多。这就是背景：

public class Context
{
    public const string DATABASE_NAME = "Test";
    public const string FIRST_COLLECTION_NAME = "FirstCollection";
    public const string SECOND_COLLECTION_NAME = "SecondCollection";

    private static readonly IMongoClient _client;
    private static readonly IMongoDatabase _database;
    static Context()
    {
        var connectionString = ConfigurationManager.AppSettings["MongoDbServer"];
        _client = new MongoClient(connectionString);
        _database = _client.GetDatabase(DATABASE_NAME);
    }

    public IMongoClient Client => _client;

    public IMongoCollection<First> FirstCollection =>
        _database.GetCollection<First>(FIRST_COLLECTION_NAME);

    public IMongoCollection<Second> SecondCollection =>
        _database.GetCollection<Second>(SECOND_COLLECTION_NAME);
}

更新

编辑后，我唯一能想到的是：

var result = context.FirstCollection.Find(x=> x.Name == "Paul").ToList();