private void AddNewReg()
 {
     string reason;
     if (!_add.IsValid(out reason))
     {
         MessageBox.Show(reason, @"Toevoegen mislukt");
     }
     else if (Data.Add(_add.ToRegistratie()))
     {
         _registraties = Data.GetRegsForDay(_date);
         _add = new Addmode(_date);
         SetMode(FormMode.View);
     }
 }
        public FormModifyReg(DateTime date, bool add)
        {
            InitializeComponent();
            btnOk.Click += (s, e) => Close();
            lblLocation.Click += (s, e) => OpenFormLoc();
            lbRegs.SelectedIndexChanged += (s, e) => SetLabels();

            _date = date;
            gbRegData.Text = _date.ToShortDateString();
            _registraties = Data.GetRegsForDay(_date);
            _add = new Addmode(_date);
            SetMode(add ? FormMode.Add : FormMode.View);
            if (add) ChangeFormToMode(_formMode);
        }