How to delete child entities before parent with Entity Framework CF?

I ended up finding a quick line that'd do it for me:

foreach (var deleteMe in deleteThese)
{ 
   // Delete validation
   if(CanDeleteItem(deleteMe.ItemId))
   {
      ///
      deleteMe.Prices.ToList().ForEach(p => db.ItemPrices.Remove(p));
      ///

      db.Entry(deleteMe).State = EntityState.Deleted;
   }
}
db.SaveChanges();

Well the most easiest solution would be to iterate through prices first and call save changes, then set the entry to delete for deleteMe and call save changes again, but have you checked out this: Entity framework code first delete with cascade? It seems to be what you want.

Curious though also why you just aren't removing the entities from the context to delete but instead setting the entry state?

Another option is to set cascade delete http://blogs.msdn.com/b/alexj/archive/2009/08/19/tip-33-how-cascade-delete-really-works-in-ef.aspx

Do something like this (not tested but hopefully you get the jist):

using (TransactionScope scope = new TransactionScope())
{    
    foreach (var deleteMe in deleteThese)
    { 
   // Delete validation
      if(CanDeleteItem(deleteMe.ItemId))
      {

         foreach (var item in deleteMe.Prices)
         {
            db.Entry(item).State = EntityState.Deleted; // cascade delete
         }
         db.SaveChanges();

         db.Entry(deleteMe).State = EntityState.Deleted;


     }
   }
   db.SaveChanges();
   scope.Complete();
}     

Additionally you could call:

db.Prices.Remove(item);

and

db.DeleteMes.Remove(deleteMe);

instead of setting the entry state. Not sure if there is a difference behind the scenes between the two though.

EF6

context.Children.RemoveRange(parent.Children)

Cascade delete in EF is dependent on cascade delete configured in relation in the database so if you don't have cascade delete configured in the database you must first load all item prices to your application and mark them as deleted.