Linq to Entities中无法构造实体或复杂类型

public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
using (aspnetdbEntities db = new aspnetdbEntities())
{
//MyModel model = new MyModel()
//{
//    Name = "andy"
//};
//     db.MyModel.Add(model);
//   db.SaveChanges();
var result = from a in db.MyModel
select new  {id=a.Id, Name=a.Name };
var result2 = from b in db.MyModel
select new MyModel { Id = b.Id, Name = b.Name };
var result3 = from c in db.MyModel
select new TestModel { id = c.Id, Name = c.Name };
var model = result.ToList().Select(a => new MyModel { Id=a.id,Name=a.Name});
var model2 = result2.ToList().FirstOrDefault();
var model3 = result3.ToList().FirstOrDefault();
var model4 = db.MyModel.Select(a=>a).ToList().FirstOrDefault();
}

}
}
class TestModel
{
public int id { get; set; }
public string Name { get; set; }
}