public UserForm(User user) : this()
		{
			isEditing = true;
			
			//populate the form
			IdField.Text = user.ID;
			IdField.IsEnabled = false;
			RoleField.SelectedIndex = Convert.ToInt32(user.ROLE_ID) - 1;
			SellerField.Text = user.SELLER_ID;
		}
		public bool Persist()
		{
			FiltrateForm();
			if (ValidateForm())
			{
				User u = new User()
				{
	             	ID = IdField.Text,
	             	PASSWORD = PasswordField.Password,
	             	ROLE_ID = Convert.ToInt64(RoleField.SelectedIndex) + 1,
	             	SELLER_ID = SellerField.Text
				};
				if (isEditing) return UserController.Instance.Update(u);
				else return UserController.Instance.Create(u);
			}
			else
			{
				FocusFirstField();
				throw new ValidationException("Не сте попълнили валидно всички полета.");
			}
		}