WPF ListBox IsSynchronizedWithCurrentItem True ScrollIntoView via behavior CallMethodAction in MVVM

 <ListBox Grid.Column="0"
          ItemContainerStyle="{StaticResource lbxItemContainerStyle}"
          ItemsSource="{Binding BooksCollection,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
          IsSynchronizedWithCurrentItem="True"
          DisplayMemberPath="Id">
     <behavior:Interaction.Triggers>
         <behavior:EventTrigger EventName="SelectionChanged">
             <behavior:CallMethodAction MethodName="ListBox_SelectionChanged" TargetObject="{Binding}"/>
         </behavior:EventTrigger>
     </behavior:Interaction.Triggers>
 </ListBox>


//cs
public void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    var lbx=sender as ListBox;
    if(lbx!=null)
    {
        if(e!=null && e.AddedItems!=null && e.AddedItems.Count>0)
        {
            var bk = e.AddedItems[0] as Book;
            if(bk!=null)
            {
                lbx.ScrollIntoView(bk);
            }
        }
    }
}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

//xaml
<Window x:Class="WpfApp13.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:behavior="http://schemas.microsoft.com/xaml/behaviors"
        WindowState="Maximized"
        xmlns:local="clr-namespace:WpfApp13"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.DataContext>
        <local:BookVM/>
    </Window.DataContext>
    <Window.Resources>
        <Style x:Key="lbxItemContainerStyle" TargetType="ListBoxItem">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="ListBoxItem">
                        <Border Name="_Border"
                                Padding="2"
                                SnapsToDevicePixels="true">
                            <ContentPresenter />
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsSelected" Value="true">
                                <Setter TargetName="_Border" Property="Background" Value="Red"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>
            <ColumnDefinition/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <ListBox Grid.Column="0"
                 ItemContainerStyle="{StaticResource lbxItemContainerStyle}"
                 ItemsSource="{Binding BooksCollection,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                 IsSynchronizedWithCurrentItem="True"
                 DisplayMemberPath="Id">
            <behavior:Interaction.Triggers>
                <behavior:EventTrigger EventName="SelectionChanged">
                    <behavior:CallMethodAction MethodName="ListBox_SelectionChanged" TargetObject="{Binding}"/>
                </behavior:EventTrigger>
            </behavior:Interaction.Triggers>
        </ListBox>
        <ListBox Grid.Column="1"
                 ItemContainerStyle="{StaticResource lbxItemContainerStyle}"
                 ItemsSource="{Binding BooksCollection,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                 IsSynchronizedWithCurrentItem="True"
                 DisplayMemberPath="Name">
            <behavior:Interaction.Triggers>
                <behavior:EventTrigger EventName="SelectionChanged">
                    <behavior:CallMethodAction MethodName="ListBox_SelectionChanged" TargetObject="{Binding}"/>
                </behavior:EventTrigger>
            </behavior:Interaction.Triggers>
        </ListBox>

        <ListBox Grid.Column="2"
                 ItemContainerStyle="{StaticResource lbxItemContainerStyle}"
                 ItemsSource="{Binding BooksCollection,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                 IsSynchronizedWithCurrentItem="True">
            <behavior:Interaction.Triggers>
                <behavior:EventTrigger EventName="SelectionChanged">
                    <behavior:CallMethodAction MethodName="ListBox_SelectionChanged" TargetObject="{Binding}"/>
                </behavior:EventTrigger>
            </behavior:Interaction.Triggers>
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Image Source="{Binding DataContext.ImgUrl,RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type ListBoxItem}}}"
                           Width="20"
                           Height="50" />
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>





//cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO;

namespace WpfApp13
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

       
    }


    public class BooksData:List<Book>
    {
        public BooksData()
        {
            var imgsList = new List<string>(Directory.GetFiles(@"../../Images"));
            if (imgsList != null && imgsList.Any())
            {
                int imgsCount=imgsList.Count;
                for(int i=0;i<100000;i++)
                {
                    Add(new Book()
                    {
                        Id = i + 1,
                        Name = $"Name_{i + 1}",
                        ImgUrl = $"{imgsList[i % imgsCount]}"
                    });
                }
            }
        }
    }

    public class BookVM : INotifyPropertyChanged
    {
        public BookVM()
        {
            InitData();
        }

        private void InitData()
        {
            var imgsList = new List<string>(Directory.GetFiles(@"../../Images"));
            if(imgsList!=null && imgsList.Any())
            {
                int imgsCount=imgsList.Count;
                BooksCollection = new ObservableCollection<Book>();
                for(int i=0;i<10000;i++)
                {
                    BooksCollection.Add(new Book()
                    {
                        Id=i+1,
                        Name=$"Name_{i+1}",
                        ImgUrl = $"{imgsList[i%imgsCount]}"
                    });
                }
            }
        }

        public void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var lbx=sender as ListBox;
            if(lbx!=null)
            {
                if(e!=null && e.AddedItems!=null && e.AddedItems.Count>0)
                {
                    var bk = e.AddedItems[0] as Book;
                    if(bk!=null)
                    {
                        lbx.ScrollIntoView(bk);
                    }
                }
            }
        }


        public event PropertyChangedEventHandler PropertyChanged;
        private void OnPropertyChanged(string propName)
        {
            var handler = PropertyChanged;
            if(handler!=null)
            {
                handler?.Invoke(this, new PropertyChangedEventArgs(propName));
            }
        }

        private ObservableCollection<Book> booksCollection;
        public ObservableCollection<Book> BooksCollection
        {
            get
            {
                return booksCollection;
            }
            set
            {
                if(value!=booksCollection)
                {
                    booksCollection = value;
                    OnPropertyChanged(nameof(BooksCollection));
                }
            }
        }
    }

    public class Book
    {
        public int Id { get; set; }

        public string Name { get; set; }

        public string ImgUrl { get; set; }
    }
}