ListBox裁剪顶部或底部

Question

ListBox seems to always crop the the last item.
For example use the arrow to move up or down or the scrollbar.

Is it possible to crop the first item if moving down and
and crop the last item if moving up?

Only supposed to be one question at a time so this is optional.
If mouse click on the last item then crop the top?
Mouse click on any other position then crop bottom.

ScrollViewer.CanContentScroll="False" fixes a lot.
Now click on item behaves as I want.
Up down arrow on items behaves like I want.
But scrollbar movement crops on both top bottom.

<Window x:Class="ListBoxLastIntoView.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <ListBox x:Name="lb" Width="420" HorizontalAlignment="Left"
                 ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Visible">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Border Width="390" BorderBrush="Purple" Padding="2" Margin="2" BorderThickness="2">
                        <TextBlock TextWrapping="Wrap" Width="380" TextTrimming="CharacterEllipsis" Text="{Binding Mode=OneWay}"/>
                    </Border>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>
namespace ListBoxLastIntoView
{
    public partial class MainWindow : Window
    {
        private string lorum = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";
        private List<string> lorums = new List<string>();
        public MainWindow()
        {
            for (int i = 1; i < 100; i++) lorums.Add(i.ToString() + " " + lorum);           
            InitializeComponent();
            lb.ItemsSource = lorums;
        }
    }
}

Answer 1

If you want to remove the blank space at the end of ListBox , you can use this construction:

<ListBox x:Name="lb"     
         ScrollViewer.CanContentScroll="False" ... />