private async void lstVIew_ItemSelected(object sender, SelectedItemChangedEventArgs e)
        {
            if (lstVIew.SelectedItem == null)
            {
                return;
            }

            var selected = (Contact)e.SelectedItem;

            lstVIew.SelectedItem = null;
            var page = new ContactDetailPage(selected);

            page.ButtonSave.Clicked += (s, f) =>
            {
                var contact = new Contact()
                {
                    FirstName   = page.EntryFirst.Text,
                    LastName    = page.EntryLast.Text,
                    PhoneNumber = page.EntryPhone.Text,
                    Email       = page.EntryEmail.Text,
                    IsBlocked   = page.SwitchBlocked.IsEnabled,
                };
                Navigation.PopAsync();
            };


            await Navigation.PushAsync(page);
        }
        private async void ToolbarItem_Clicked(object sender, EventArgs e)
        {
            var page = new ContactDetailPage();

            page.ButtonSave.Clicked += (s, f) =>
            {
                var contact = new Contact()
                {
                    FirstName   = page.EntryFirst.Text,
                    LastName    = page.EntryLast.Text,
                    PhoneNumber = page.EntryPhone.Text,
                    Email       = page.EntryEmail.Text,
                    IsBlocked   = page.SwitchBlocked.IsEnabled,
                };
                _contacts.Add(contact);
                Navigation.PopAsync();
            };
            await Navigation.PushAsync(page);
        }