Re: [mongodb-user] C# Driver: "Ensure that known types are derived from the mapped class." error

[Robert Stam]

[BsonKnownTypes] is used to list known *subclasses* of a root class.

Try just removing the [BsonKnownTypes] and see how that works.

If there is still an issue after that, please provide a stack trace also.

Thanks.

On Sat, Oct 6, 2012 at 9:46 AM, Dan Terrill <dan.t...@c8sciences.com> wrote:

Folks,

I just started working on a game as a hobby project, and when I execute this query:

 if(gameCollection.Any(g => g.NumPlayers < GameConstants.MAX_PLAYERS_PER_GAME))

            {

                return gameCollection.First(g => g.NumPlayers < GameConstants.MAX_PLAYERS_PER_GAME);

            }

I get the error "

Class MOMGame.GameObjects.Map cannot be assigned to Class MOMGame.GameObjects.Game.  Ensure that known types are derived from the mapped class.
Parameter name: type"

Any idea what I'm doing wrong? The 2 classes are pretty simple, and listed below.

Game:

[BsonKnownTypes(typeof(MOMGame.GameObjects.Map), typeof(MOMGame.GameObjects.Location), typeof(MOMGame.GameObjects.Game), typeof(MOMGame.GameObjects.UserInfo))]

    public class Game 

    {

        [BsonId]

        public Guid Id { get; set; }

        public  Map Map { get; set; }

        

        public string Name { get; set; }

         

        public List<Guid> Players { get; set; }

        [BsonRepresentation(BsonType.Int32)]

        public int NumPlayers { get; set; }

        public Game()

        {

            Players = new List<Guid>();

            //if (!BsonClassMap.IsClassMapRegistered(typeof(Game)))

            //{

            //    BsonClassMap.RegisterClassMap<Game>(cm => cm.AutoMap());

            //}

        }

        public static void SaveGame(Game game)

        {

            var connectionString = "mongodb://localhost/?safe=true";

            var server = MongoServer.Create(connectionString);

            var database = server.GetDatabase("mom");

            var gameCollection = database.GetCollection<Game>("games");

            game.NumPlayers = game.Players.Count;

            gameCollection.Save(game);

        }

        public static Game GetNextGame()

        {

            var connectionString = "mongodb://localhost/?safe=true";

            var server = MongoServer.Create(connectionString);

            var database = server.GetDatabase("mom");

            var gameCollection = database.GetCollection<Game>("games").AsQueryable();

            if(gameCollection.Any(g => g.NumPlayers < GameConstants.MAX_PLAYERS_PER_GAME))

            {

                return gameCollection.First(g => g.NumPlayers < GameConstants.MAX_PLAYERS_PER_GAME);

            }

            else

            {

                return GameCreator.CreateGame();

            }

        }

    }

Map:

[BsonKnownTypes(typeof(MOMGame.GameObjects.Map), typeof(MOMGame.GameObjects.Location) , typeof(MOMGame.GameObjects.Game),  typeof(MOMGame.GameObjects.UserInfo))]

    public class Map 

    {

        public Map()

        {

            //if (!BsonClassMap.IsClassMapRegistered(typeof(Map)))

            //{

            //    BsonClassMap.RegisterClassMap<Map>(cm => cm.AutoMap());

            //}

        }

        [BsonIgnore]

        public ILocation[][] Grid { get; set; }

        [BsonId]

        public Guid Id { get; set; }

        public string Name { get; set; }

        [BsonIgnore]

        public List<ILocation> Locations

        {

            get

            {

                List<ILocation> locs = new List<ILocation>();

                for (int i = 0; i < Grid.Length; i++)

                {

                    for (int j = 0; j < Grid[i].Length; j++)

                    {

                        locs.Add(Grid[i][j]);

                    }

                }

                return locs;

            }

        }

    }

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