Linq to Entities中无法构造实体或复杂类型

 1   public partial class WebForm1 : System.Web.UI.Page
 2     {
 3         protected void Page_Load(object sender, EventArgs e)
 4         {
 5             using (aspnetdbEntities db = new aspnetdbEntities())
 6             {
 7                 //MyModel model = new MyModel()
 8                 //{
 9                 //    Name = "andy"
10                 //};
11                 //     db.MyModel.Add(model);                
12              //   db.SaveChanges();
13                 var result = from a in db.MyModel
14                              select new  {id=a.Id, Name=a.Name };
15                 var result2 = from b in db.MyModel
16                               select new MyModel { Id = b.Id, Name = b.Name };
17                 var result3 = from c in db.MyModel
18                               select new TestModel { id = c.Id, Name = c.Name };
19                 var model = result.ToList().Select(a => new MyModel { Id=a.id,Name=a.Name});
20                 var model2 = result2.ToList().FirstOrDefault();
21                 var model3 = result3.ToList().FirstOrDefault();
22                 var model4 = db.MyModel.Select(a=>a).ToList().FirstOrDefault();
23             }
24         
25         }
26     }
27     class TestModel
28     {
29         public int id { get; set; }
30         public string Name { get; set; }
31     }