protected void btnDelete_Click(object sender, EventArgs e)
 {
     try
     {
         AddressBookRepository context = new AddressBookRepository();
         context.DeletePersonByID(1);
         GetPeople();
         lblError.Text = "Contact deleted.";
     }
     catch (OptimisticConcurrencyException)
     {
         lblError.Text = "There was an error while deleting record from database. The record you attempted to delete was modified by another " +
                         "user after you got the original value. The delete operation was canceled.";
     }
     catch (ArgumentNullException)
     {
         lblError.Text = "There was an error while deleting record from database. Make sure that user exist.";
     }
     catch (Exception)
     {
         lblError.Text = "There was an error while deleting record from database. Please try again.";
     }
 }
        protected void contactsGridView_RowDeleting(object sender, GridViewDeleteEventArgs e)
        {
            // int index = e.RowIndex; // index of the row to delete -> where Delete button clicked
            int personID = Convert.ToInt32(contactsGridView.DataKeys[e.RowIndex].Value);

            try
            {
                AddressBookRepository context = new AddressBookRepository();
                context.DeletePersonByID(personID);
                GetPeople();
                lblError.Text = "Contact " + " " + e.Values["FirstName"] + " " + e.Values["LastName"] + " deleted!";
            }
            catch (OptimisticConcurrencyException)
            {
                lblError.Text = "There was an error while deleting record from database. The record you attempted to delete was modified by another " +
                                 "user after you got the original value. The delete operation was canceled.";
            }
            catch (ArgumentNullException)
            {
                lblError.Text = "An error occured while deleting contact. Make sure that contact exists.";
            }
            catch (Exception)
            {
                lblError.Text = "An error occured while deleting contact. Please try again.";
            }
        }