Not showing items with Visibility=Collapsed in Windows Phone 8.1 ListView

Question

I have a problem with my ListView. I bind the ItemsSource to my ViewModel but I want items that have a certain property set to null to be completely collapsed (as in the whole item is collapsed, not just the control that is bound the the property that might be null). I have a converter that works but the ListView still seems to reserve at least some space for items that are collapsed. This results in my ListView having ugly "holes". (Please note that the holes do not take up as much space as the visible items but they do take up some space and the "invisible" items are even clickable...)

My problem is pretty much the same as the one stated here: Not showing items with Visibility=Collapsed in Windows 8.1 GridView

The only thing that bothers me is that the OP of the linked question says, that for him it's working fine in Windows Phone but not in Windows. Well for me it's not working in Windows Phone. Any suggestions what I could do?

The Code:

    <DataTemplate x:Key="UpcomingEpisodesTemplate">
        <Grid Visibility="{Binding Upcoming, Converter={StaticResource EpisodeVisibilityConverter}}">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="110"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
             ....The rest of the template which is not important...
        </Grid>
    </DataTemplate>

Thanks!

kober kober · Accepted Answer · 2015-04-28T14:30:02

You could try convert whatever you binding to ItemsSource. Like this:

<ListView
    ItemsSource={Binding MyList, Converter={StaticResource MyListConverter}}>

With converter like this.

public class MyListConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        return ((IEnumerable<MyType>)value).Where(x => x.MyProperty != null);
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        return null;
    }
}

Edit with ObservableCollection.

public class MyListConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        var originalObservable = (ObservableCollection<MyType>)value;

        var collection = new ObservableCollection<MyType>();

        collection.AddRange(originalObservable.Where(x => x.MyProperty != null));

        originalObservable.CollectionChanged += delegate { collection.Clear(); collection.AddRange(originalObservable.Where(x => x.MyProperty != null)); };

        return collection;
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        return null;
    }
}

Not showing items with Visibility=Collapsed in Windows Phone 8.1 ListView

3 Answers