Xamarin形式的可扩展ListView

Question

I have the following code to display a ListView using Xamarin Forms:

App.cs

public App ()
{
    MainPage = GetMainPage();
}

public static Page GetMainPage()
{
    return new NavigationPage(new DrilldownListViewByItem());
}

DrilldownListViewByItem:

public class DrilldownListViewByItem : ContentPage
{
    public DrilldownListViewByItem()
    {
        Title = "Drilldown List Using ListView";
        var listView = new ListView();
        listView.ItemsSource = new ListItem[] {
            new ListItem {Title = "First", Description="1st item"},
            new ListItem {Title = "Second", Description="2nd item"},
            new ListItem {Title = "Third", Description="3rd item"}
            };
        listView.ItemTemplate = new DataTemplate(typeof(TextCell));
        listView.ItemTemplate.SetBinding(TextCell.TextProperty, "Title");

        listView.ItemTapped += async (sender, args) =>
        {
            var item = args.Item as ListItem;
            //if (item == null) return;
            //await Navigation.PushAsync(new DetailPage(item));
            //listView.SelectedItem = null;
        };
        Content = listView;
    }
}

ListItem has these properties:

public string Title { get; set; }
public string Description { get; set; }

What I want to do is to show subitems when I tab on one of the main items. These subitems should be hidden at the beggining, but they should be there, I don't want to load them every time I tab on an item. Any idea? Thanks!

Answer 1

Try changing the visibility of the items you want to appear and disappear based on the click event of the list item.

On iOS you may also have to change the cell height (using HeightRequest), because it is likely that it won't change on it's own. I am guessing that android will work just fine.

Hope this helps.