小编The*_*her的帖子

我试图将用户选择的选择器值发送到列表.该列表应继续添加用户选择的内容,而不是删除之前的内容.关于如何做到这一点的任何提示？

 private void MainPicker_SelectedIndexChanged(object sender, EventArgs e)
        {

             var product = MainPicker.Items[MainPicker.SelectedIndex];
             DisplayAlert(product, "Layer added to calculation list", "OK");

        }
 private void ListView_ItemSelected(object sender,SelectedItemChangedEventArgs e)
        {
            if (e.SelectedItem == null)
           // if selected add to list?

        }