Question

我是entityframework的新手，我从这段代码开始，但我不知道为什么我有一个异常处理程序＆＃34; System.Data.Entity.ModelConfiguration.ModelValidationException＆＃39;发生在EntityFramework.dll＆＃34; in line var count = context.Albums.Count（）;

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Data.Entity;

    namespace entityframework1
      {
        class Program
         {
           static void Main(string[] args)
            {
              using (var context = new MusicAlbumContext())
                 {
                      var count = context.Albums.Count();
                      Console.WriteLine(count);
                      context.Albums.Add(new Album() { Name = "best", Cost = 34.43m });
                     context.SaveChanges();
                     Console.WriteLine(count);
                     Console.Read();
        }
    }
}



      public  class MusicAlbumContext:DbContext
        {
          public DbSet<Album> Albums { get; set; }
        }

     public   class Album
       {
        public string Name { get; set; }
        public decimal Cost { get; set; }
}

}

Answer 1

您需要执行以下过程

class Program
     {
       static void Main(string[] args)
        {
          using (var context = new MusicAlbumContext())
             {
                  var count = context.Albums.Count();
                  Console.WriteLine(count);
                  context.Albums.Add(new Album() { Name = "best", Cost = 34.43m });
                 context.SaveChanges();
                 Console.WriteLine(count);
                 Console.Read();
    }
}

}

  public  class MusicAlbumContext:DbContext
    {
      public MusicAlbumContext()
        : base("connectionstring")
    {

    }
    static MusicAlbumContext()
{
    Database.SetInitializer(new DropCreateDatabaseIfModelChanges<MusicAlbumContext>());
}
      public DbSet<Album> Albums { get; set; }
    }

 public   class Album
   {
    public string Name { get; set; }
    public decimal Cost { get; set; }

}

之后运行以下commnads enable-migrations contextname add-migration InitialCreate update-database -verbose -fource

System.Data.Entity.ModelConfiguration.ModelValidationException＆＃39;发生在c＃consol应用程序中的EntityFramework.dll中

1 个答案: