Working with _id in .Net

Update:

I was looking at how this happened and I need some clarification. In the .Net project, in the classes (user, store, product) the id field has the following entered:

 [BsonElement("_id")]
        [JsonProperty("_id")]
        [BsonId]
        [BsonRepresentation(BsonType.ObjectId)]
        public string Id { get; set; }

Because of this I thought that the _id : “60ff64082fe05c5723b9ab4e” needed to be in Mongo as a string since it is a string in the VS project.

Since it is a string, it errors out when trying to use the _id field. (The system says it needs it to be an Object) is there any documentation on how to effectively use this field in your program? I like the field due to its high cardinality.

Dave