private void Button_Click(object sender, RoutedEventArgs e)
{
ctx.ObjectStateManager.GetObjectStateEntries(System.Data.EntityState.Modified).Select(c => c.Entity).OfType <OrderDetail>().Where(c => c.Order == null).ToList().ForEach(c => ctx.DeleteObject(c));
ctx.DetectChanges();
MessageBox.Show(orderDataGrid.Items.Count.ToString() + "-" +
ctx.ObjectStateManager.GetObjectStateEntries(System.Data.EntityState.Added).Count() + "-" +
ctx.ObjectStateManager.GetObjectStateEntries(System.Data.EntityState.Modified).Count() + "-" +
ctx.ObjectStateManager.GetObjectStateEntries(System.Data.EntityState.Deleted).Count());
//ctx.SaveChanges();
}