How to query inside Array in MongoDB Collection using C#?

Question

I am trying to traverse into a MongoDB Collection of the form :

{"_id":"lkashfhasdfhsdlafhlkjsdahf",
"
"Array":[{

                    "array_1":"17:00"}],

}

I want to get the array_1 in the document above I tried it using the following code in C#

result = Database.CollectionName.AsQueryable().Where(r => r.Array.array== array_inpit(Input) && condition2).ToList();

Expected Result : All the documents with the matching Array

Current Output : Error

Any help how should i proceed with this.

Greg Stanley · Accepted Answer · 2019-04-01T15:01:36.713

Basic example using the MongoDb.Driver package. You'll need some data types defined, something like:

// Use [BsonIgnoreExtraElements] attribute when not defining ALL fields in record
internal class MainRecord
{
    public ObjectId _id { get; set; }

    public List<ArrayItem> ResourceStatus { get; set; }

    // All the other fields here
}

// [BsonIgnoreExtraElements] as above
internal class ArrayItem
{
    public string E2EId { get; set; }
}

(Note - I've omitted all the fields not required to do the array search).

Then to actually query the data:

var client = new MongoClient();

IMongoDatabase db = client.GetDatabase("database-name-here");

var collectionName = "collection-name-here";

IMongoCollection<MainRecord> collection = db.GetCollection<MainRecord>(collectionName);

var filter = Builders<MainRecord>.Filter.ElemMatch(x => x.ResourceStatus, x => x.E2EId == "1fdsfsfsfsfsffds0");

var result = collection.Find(filter);

EDIT: And I'd recommend looking at this post which gives some alternative approaches.

score 0 · Answer 2 · answered Apr 01 '19 at 15:15

I create simple classes do demonstrate how to:

MongoDB Class

public class MongoDBConnect : IDisposable
{
    public IMongoClient client;
    public IMongoDatabase database;

    public MongoDBConnect()
    {
        client = new MongoClient("mongodb://localhost");
        database = client.GetDatabase("dbo");
    }

    public void Dispose()
    {
        GC.WaitForPendingFinalizers();
        GC.Collect();
    }
}

Your Collection Class

public class YourCollection
{
    [BsonId()]        
    public ObjectId Id { get; set; }

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

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

Your Collection Data Class

public class YourCollectionDAO : MongoDBConnect
{
    public YourCollectionDAO()
    {

    }

    public YourCollection Find(string yourCollectionID)
    {
        var collection = this.database.GetCollection<User>("YourCollection");

        Expression<Func<YourCollection, bool>> filter = x => x.yourCollectionID == yourCollectionID;

        IList<YourCollection> filtering = collection.Find(filter).ToList();

        var yourCollectionItem = filtering.Where(x => x.yourCollectionID == yourCollectionID).FirstOrDefault();

        return yourCollectionItem;
    }
}

Hope it helps.

How to query inside Array in MongoDB Collection using C#?

2 Answers2