Zentrieren ausgewählte Element in einer scroll-viewer

Versuchen ListView.ScrollIntoView() oder ListView.MakeVisible ersten Blättern den container des Elements in anzeigen und umgehen, die möglicherweise virtualisierte aus der UI. Dann verwenden
ListView.ItemContainerGenerator . ContainerFromIndex() , um die container von den Artikel und dann den VisualTreeHelper um seine position relativ zu den ScrollViewer. Dann scrollen Sie in der scrollviewer um den berechneten offset.

*BEARBEITEN - Beispiel Positionier-Logik:

Holen Sie sich die VisualTreeHelperExtensions von WinRT XAML Toolkit, um Zugang zu den ScrollViewer leicht mit GetFirstDescendantOfType() Erweiterung Methode umschließt, die einige Aufrufe an die VisualTreeHelper.

XAML

<Page
    x:Class="ListViewItemCentering.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:ListViewItemCentering"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid
        Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <ListView
            x:Name="listView">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <Border
                        Width="400"
                        Height="100">
                        <ContentControl
                            Content="{Binding}"
                            FontSize="48"
                            Padding="20,10"/>
                    </Border>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

        <Button
            Content="Skip"
            Width="200"
            Height="100"
            HorizontalAlignment="Right"
            VerticalAlignment="Bottom"
            Click="ButtonBase_OnClick"/>
    </Grid>
</Page>

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using WinRTXamlToolkit.Controls.Extensions;

namespace ListViewItemCentering
{
    ///<summary>
    ///An empty page that can be used on its own or navigated to within a Frame.
    ///</summary>
    public sealed partial class MainPage : Page
    {
        private Random random = new Random();
        public MainPage()
        {
            this.InitializeComponent();
            this.listView.ItemsSource = Enumerable.Range(1, 1000);
            this.listView.SelectionChanged += OnListViewSelectionChanged;
        }

        private async void OnListViewSelectionChanged(object sender, SelectionChangedEventArgs selectionChangedEventArgs)
        {
            if (listView.SelectedItem == null)
            {
                return;
            }

            var item = listView.SelectedItem;

            //Calculations relative to screen or ListView
            var listViewItem = (FrameworkElement)listView.ContainerFromItem(item);

            if (listViewItem == null)
            {
                listView.ScrollIntoView(item);
            }

            while (listViewItem == null)
            {
                await Task.Delay(1); //wait for scrolling to complete - it takes a moment
                listViewItem = (FrameworkElement)listView.ContainerFromItem(item);
            }

            var topLeft =
                listViewItem
                    .TransformToVisual(listView)
                    .TransformPoint(new Point()).Y;
            var lvih = listViewItem.ActualHeight;
            var lvh = listView.ActualHeight;
            var desiredTopLeft = (lvh - lvih) / 2.0;
            var desiredDelta = topLeft - desiredTopLeft;

            //Calculations relative to the ScrollViewer within the ListView
            var scrollViewer = listView.GetFirstDescendantOfType<ScrollViewer>();
            var currentOffset = scrollViewer.VerticalOffset;
            var desiredOffset = currentOffset + desiredDelta;
            scrollViewer.ScrollToVerticalOffset(desiredOffset);

            //better yet if building for Windows 8.1 to make the scrolling smoother use:
            //scrollViewer.ChangeView(null, desiredOffset, null);
        }

        private async void ButtonBase_OnClick(object sender, RoutedEventArgs e)
        {
            this.listView.SelectedIndex = random.Next(0, ((IEnumerable<int>)this.listView.ItemsSource).Count());
        }
    }
}