When insert document causes LiteException.

When i try to insert document on collection cause LiteException:

LiteDB.LiteException: Invalid BSON data type ‘Null’ on field ‘_id’. at LiteDB.LiteEngine.InsertDocument(CollectionPage col, BsonDocument doc, BsonType autoId) at LiteDB.LiteEngine.<>cDisplayClass22_0.<Insert>b0(CollectionPage col) at LiteDB.LiteEngine.Transaction[T](String collection, Boolean addIfNotExists, Func2 action) at LiteDB.LiteEngine.Insert(String collection, BsonDocument doc, BsonType autoId) at LiteDB.LiteCollection1.Insert(T document) at ForGer.Modules.DeveloperModule.CadastraTodosAsync(CommandContext ctx) in C:\Users\Nathan Ferreira\Desktop\ForGer\ForGer\Modules\DeveloperModule.cs:line 48 at DSharpPlus.CommandsNext.Command.ExecuteAsync(CommandContext ctx)

Class:

	public class Usuario
	{
		[BsonId]
		protected ObjectId _id;

		[BsonField("user_id")]
		private string _user_id;

		[BsonIgnore]
		public ulong UserId {
			get { return ulong.Parse(_user_id); }
			set { _user_id = value.ToString(); }
		}

		[BsonField("experience")]
		public long Experience { get; set; }
	}

Insert method:

var user = new User();
user.UserId  = 235088799074484224;
user.Experience = 62754;

var mapper = new BsonMapper();
mapper.IncludeNonPublic = true; // accepts protected, internal and private fields.

var db = new LiteDatabase("Users.db", mapper);
var col = db.GetCollection<Usuario>();
col.Insert(user); // Causes LiteException Invalid BSON data type 'Null' on field '_id'.

Same exception in this class: (Using no protected fields)

public class Usuario
{
	[BsonId]
	public ObjectId _id;

	[BsonField("user_id")]
	public ulong UserId { get; set; }

	[BsonField("experience")]
	public long Experience { get; set; }
}

No way to auto create an object id?

[lilasquared]

@nathan130200 make your _id field a property and it should work, or use the BsonMapper.Global.IncludeFields = true option

[nathan130200]

Fixed! Thanks for help.