问发布新条目时的ASP.net一切都很好，但在之后调用时，数据就消失了

EN

public class Game
{
    public Game()
    {
        GameLocations = new List<Location>();
        GameSuspects = new List<Suspect>();
        GameClues = new List<Clue>();
    }

    [Key]
    public int GameId { get; set; }    
    public bool GameWon { get; set; }


    public ICollection<Location> GameLocations { get; set; }
    public ICollection<Suspect> GameSuspects { get; set; }
    public ICollection<Clue> GameClues { get; set; }

}

public class Location
{
    public double LocLat { get; set; }
    public double LocLong { get; set; }
    public string LocDescription { get; set; }
    public string LocName { get; set; }
    //public ICollection<GameLocation> GameLocations { get; set; }

    [Key]
    public int LocId { get; set; }
}

    [HttpPost("newgame")]
    public IActionResult CreateNewGame()
    {
        var newGame = new Game();

        // add random locations
        var location1 = _dbcontext.Locations.Find(1);
        var location2 = _dbcontext.Locations.Find(3);

        newGame.GameLocations.Add(location1);
        newGame.GameLocations.Add(location2);            

        //add suspects
        var suspect1 = _dbcontext.Suspects.Find(1);
        var suspect2 = _dbcontext.Suspects.Find(2);

        newGame.GameSuspects.Add(suspect1);
        newGame.GameSuspects.Add(suspect2);

        //add Clues
        var clue1 = _dbcontext.Clues.Find(1);
        var clue2 = _dbcontext.Clues.Find(2);

        newGame.GameClues.Add(clue1);
        newGame.GameClues.Add(clue2);

        _dbcontext.Games.Add(newGame);
        _dbcontext.SaveChanges();

        return Created("", newGame);
    }

    [HttpGet("getGames")]
    public ActionResult<List<Game>> GetGames()
    {
        return _dbcontext.Games.ToList();
    }