MongoDB driver with DocumentDB

dotnotation.cs

using System;
using MongoDB.Bson;
using MongoDB.Driver;

namespace ConsoleApp1
{
	public class Program
	{
		public static void Main(string[] args)
		{

			MongoClient client = new MongoClient("<CONNETION STRING>");
			var database = client.GetDatabase("test-db");

			var userId = Guid.NewGuid();
			var documentId = Guid.NewGuid();

			var collection = database.GetCollection<BsonDocument>("test-collection");

	
			var doc = new BsonDocument
			{
				{"_id", documentId },
				{ "members",
					new BsonArray {
						new BsonDocument() {
							{ "userId", userId }
						}
					}
				}
			};

			collection.InsertOneAsync(doc).Wait();
			Console.WriteLine("Inserted document, press any key to find document");

			Console.ReadKey();

			var filter = Builders<BsonDocument>.Filter.Eq("_id", documentId);
			var result = collection.FindAsync(filter).Result.FirstOrDefault();

			Console.WriteLine("Find by id:");
			Console.WriteLine(result);
				
			var filter2 = Builders<BsonDocument>.Filter.Eq("members.userId", userId);
			var result2 = collection.FindAsync(filter2).Result
				.FirstOrDefault();

			Console.WriteLine("Find by userId:");
			// Expecting to find the document again.
			Console.WriteLine(result2 == null ? "No results" : result2.ToString());
			Console.ReadLine();
		}
	}
}