从ObjectID列表中查找所有MongoDB文档

Question

I am trying to find all documents from a MongoDB database, which has the ObjectID from my list of IDs with C#. Here's what I'm trying:

public IEnumerable<Product> GetFromIDs(List<string> productIDs)
{
    var client = new MongoClient(new MongoUrl("mongodb://localhost:27017"));
    var db = client.GetDatabase("Database");
    var products = db.GetCollection<Product>("Products")
        .Find(x => x._id == productIDs)
        .ToEnumerable();
    return products;
}

productIDs is simply a list of ObjectIDs from the MongoDB database. Obviously trying to find by a list of IDs doesn't work that way, as it takes a single parameter.

How do I .Find() all the documents from my list of product IDs?

Answer 1

This is the strongly-typed way.

public IEnumerable<Product> GetFromIDs(List<string> productIDs)
{
    var client = new MongoClient(new MongoUrl("mongodb://localhost:27017"));
    var db = client.GetDatabase("Database");
    var productsCollection = db.GetCollection<Product>("Products");

    var productObjectIDs = productIDs.Select(id => new ObjectId(id));

    var filter = Builders<Product>.Filter
        .In(p => p.Id, productObjectIDs);

    var products = productsCollection
        .Find(filter)
        .ToEnumerable();

    return products;
}

Answer 2

I figured out a pretty hacky solution. Not one of my proudest moments to be honest:

ObjectId[] allIDs = new ObjectId[productIDs.Count];

for(var i = 0; i < productIDs.Count; i++)
{
    allIDs[i] = new ObjectId(productIDs[i]);
}

var filter = new BsonDocument("_id", new BsonDocument("$in", new BsonArray(allIDs)));
var products = db.GetCollection<Product>("Products").Find(filter).ToEnumerable();

But hey, it works .