public class MongoDBManager
    {
        Mongo driver = new Mongo();

        MongoDB.Driver.Database currentDatabase;

        public MongoDBManager(string database)
        {
            driver = new Mongo();
            driver.Connect();
            currentDatabase = driver[database];
        }

        public T FindOne<T>(T specs) where T : IMongoPersistableObject
        {
            IMongoCollection c = GetCollection<T>();
            Document spec = ConvertSpecsToDocument(specs);
            Document result = c.FindOne(spec);
            if (result != null)
                return ConvertFromDocument<T>(result);
            return default(T);
        }

        public IEnumerable<T> Find<T>(T specs) where T : IMongoPersistableObject
        {
            IMongoCollection c = GetCollection<T>();
            Document specDocument = ConvertSpecsToDocument(specs);
            ICursor results = c.Find(specDocument);
            foreach (Document document in results.Documents)
            {
                yield return ConvertFromDocument<T>(document);
            }
        }

        private T ConvertFromDocument<T>(Document result) where T : IMongoPersistableObject
        {
            T o = Activator.CreateInstance<T>();
            foreach (var field in typeof(T).GetFields())
            {
                object val;
                if ((val = result[field.Name]) != null)
                    field.SetValue(o, val);
            }
            IMongoPersistableObject mpo = (IMongoPersistableObject)o;
            mpo.DatabaseId = (Oid)result["_id"];
            return o;
        }


        private Document ConvertToDocument<T>(T o)
        {
            Document doc = new Document();
            foreach (var field in typeof(T).GetFields())
            {
                doc.Add(field.Name, field.GetValue(o));
            }
            return doc;
        }

        private Document ConvertSpecsToDocument<T>(T specs)
        {
            Document doc = new Document();
            foreach (var field in typeof(T).GetFields())
            {
                object value = field.GetValue(specs);
                if (value != null)
                    doc.Add(field.Name, value.ToString());
            }
            return doc;
        }

        private IMongoCollection GetCollection<T>()
        {
            return currentDatabase.GetCollection(typeof(T).FullName);
        }

        public T Persist<T>(T o) where T : IMongoPersistableObject
        {
            IMongoPersistableObject mpo = (IMongoPersistableObject)o;
            if (mpo.DatabaseId == null)
            {
                return Insert<T>(o);
            }
            else
            {
                return Update<T>(o);
            }
        }

        private T Insert<T>(T o) where T : IMongoPersistableObject
        {
            IMongoCollection table = GetCollection<T>();
            table.Insert(ConvertToDocument(o));
            return o;
        }

        private T Update<T>(T o) where T : IMongoPersistableObject
        {
            IMongoCollection table = GetCollection<T>();
            Document d = ConvertToDocument<T>(o);
            IMongoPersistableObject mpo = (IMongoPersistableObject)o;
            d["_id"] = mpo.DatabaseId;
            table.Update(d);
            return o;
        }
    }