How to work with multiple DbSets with a common base class in EF 5?

Question

How to work with multiple DbSets with a common base class in EF 5?

I have 2 POCO classes:

class Email: Base { public int SomeProperty { get; set; } } class Photo: Base { public int SomeOtherProperty { get; set; } }

and base class

 abstract class Base { public DateTime DateCreated { get; set; } }

here is my context definition:

 public class EntitiesContext : DbContext { public DbSet<Email> Emails { get; set; } public DbSet<Photo> Photos { get; set; } }

Of course, these classes are just for example, things are more complicated.

the base class is intended only for common properties for each changed table, state, etc. I believe that I am using the Table-Per-Type approach.

PROBLEM: I have a common business logic that I need to run against each table (for example, count the raw elements of each type). I need a way to iterate through a set of tables with a common base class. I was hoping to do something like this:

 private void GoThroughAllTables(Action<DbSet<Base>> fnProcess, bool needSave) { using (var db = new EntitiesContext()) { fnProcess(db.Emails); fnProcess(db.Photos); if (needSave == true) { db.SaveChanges(); } } } public IEnumerable<QueueStatus> GetQueueStatus() { var res = new List<QueueStatus>(); GoThroughAllTables((set) => { res.Add(new QueueStatus { Count = set.Cast<Base>().Count(x => x.DateCreated > someDate), }); }, false); return res; } public void DeleteFailedItems() { GoThroughAllTables((set) => { set.Cast<Base>().Remove(x => x.DateCreated > someDate); }, true); return res; }