Question

为什么我在这个上遇到错误？我想要类型的ID ...在数据库中，游戏表在类型表中有genre_id的外键。

 public List<Game> GetGames()
    {
        List<Game> games = new List<Game>();
        try
        {
            conn.Open();

            string selectQuery = "select * from game";
            MySqlCommand cmd = new MySqlCommand(selectQuery, conn);
            MySqlDataReader dataReader = cmd.ExecuteReader();

            while (dataReader.Read())
            {
                string gameNaam = dataReader.GetString("gamenaam");
                int gameId = dataReader.GetInt32("game_id");
                int genreId = dataReader.GetInt32("genre_id");
                Game game = new Game { ID = genreId, game.Genre.ID = genreId, Naam = gameNaam};

                games.Add(game);
            }
        }
        catch (Exception e)
        {
            Console.Write("Ophalen van genres mislukt " + e);
        }
        finally
        {
            conn.Close();
        }

        return games;
    }
}

我在这个上面收到错误-----＆gt; game.Genre.ID = genreId

代码类型和游戏：

   public class Game 
{
    public String Naam { get; set; }

    public Genre Genre { get; set; }

    public int ID { get; set; }

    public override string ToString()
    {
        return String.Format("{0} (id = {1})", Naam, ID);
    }
}

 public class Genre
{
    public string Naam { get; set; }
    public bool Verslavend { get; set; }
    public int ID { get; set; }

    public override String ToString()
    {
        return String.Format("{0} ({1})", Naam,
            Verslavend ? "Verslavend" : "Niet verslavend");
    }

  }

Answer 1

这是无效的语法：

new Game { ID = genreId, game.Genre.ID = genreId, Naam = gameNaam};
                         ^--- here

game在该上下文中不存在。你也不能在这样的属性初始化器中设置子属性。

如果要设置Genre属性，则必须自行设置。像这样：

new Game {
  ID = genreId,
  Genre = new Genre {
    ID = genreId
  },
  Naam = gameNaam
};

从c＃中的另一个类中获取对象ID

1 个答案: