When using a CollectionViewSource, when the Source is updated, the first item in the bound ListBox is automatically selected

Question

When binding a ListBox to a CollectionViewSource (for view filtering), when re-binding to the Source property, the ListBox automatically selects the first item (causing the SelectedItem binding to also fire).

I do not want the first item in my list to automatically select, nor do I want the setter for SelectedItem to fire at all (as I have other logic that gets called when an item is selected).

Here is a self-contained example, drop this inside a blank, new WPF application to demonstrate:

using System.Collections.Generic;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Data;

namespace TestBinding
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            var template = new DataTemplate();
            FrameworkElementFactory tbFactory = new FrameworkElementFactory(typeof(TextBlock));
            tbFactory.SetBinding(TextBlock.TextProperty, new Binding("Name"));
            template.VisualTree = tbFactory;

            var itemsA = new List<Item>
            {
                new Item { Name = "A Item 1" },
                new Item { Name = "A Item 2" },
                new Item { Name = "A Item 3" },
                new Item { Name = "A Item 4" },
                new Item { Name = "A Item 5" },
                new Item { Name = "A Item 6" },
            };
            var itemsB = new List<Item>
            {
                new Item { Name = "B Item 1" },
                new Item { Name = "B Item 2" },
                new Item { Name = "B Item 3" },
                new Item { Name = "B Item 4" },
            };
            var itemsC = new List<Item>
            {
                new Item { Name = "C Item 1" },
                new Item { Name = "C Item 2" },
                new Item { Name = "C Item 3" },
                new Item { Name = "C Item 4" },
                new Item { Name = "C Item 5" },
                new Item { Name = "C Item 6" },
                new Item { Name = "C Item 7" },
                new Item { Name = "C Item 8" },
            };

            var sp = new StackPanel();
            var b1 = new Button
            {
                Content = "Bind A"
            };
            b1.Click += (_, __) =>
            {
                Items = itemsA;
            };
            var b2 = new Button
            {
                Content = "Bind B"
            };
            b2.Click += (_, __) =>
            {
                Items = itemsB;
            };
            var b3 = new Button
            {
                Content = "Bind C"
            };
            b3.Click += (_, __) =>
            {
                Items = itemsC;
            };

            var list = new ListBox
            {
                ItemTemplate = template
            };

            list.SetBinding(ItemsControl.ItemsSourceProperty, new Binding("ItemFilter.View")
            {
                Source = this
            });
            list.SetBinding(Selector.SelectedItemProperty, new Binding("SelectedItem")
            {
                Source = this
            });

            sp.Children.Add(b1);
            sp.Children.Add(b2);
            sp.Children.Add(b3);
            sp.Children.Add(list);

            (Content as Grid).Children.Add(sp);

            ItemFilter = new CollectionViewSource();

            DataContext = this;
        }

        private List<Item> _Items;
        public List<Item> Items
        {
            get { return _Items; }
            set
            {
                _Items = value;
                ItemFilter.Source = _Items;
            }
        }

        #region Dependency Properties

        public static readonly DependencyProperty SelectedItemProperty = DependencyProperty.Register("SelectedItem", typeof(Item), typeof(MainWindow), new PropertyMetadata(default(Item)));
        public Item SelectedItem
        {
            get { return (Item)GetValue(SelectedItemProperty); }
            set { SetValue(SelectedItemProperty, value); }
        }

        public static readonly DependencyProperty ItemFilterProperty = DependencyProperty.Register("ItemFilter", typeof(CollectionViewSource), typeof(MainWindow), new PropertyMetadata(default(CollectionViewSource)));
        public CollectionViewSource ItemFilter
        {
            get { return (CollectionViewSource)GetValue(ItemFilterProperty); }
            set { SetValue(ItemFilterProperty, value); }
        }

        #endregion
    }

    public class Item : INotifyPropertyChanged
    {
        private string _Name;
        public string Name
        {
            get { return _Name; }
            set { NotifyPropertyChanged(ref _Name, value, "Name"); }
        }

        #region INPC

        public event PropertyChangedEventHandler PropertyChanged;
        public void NotifyPropertyChanged<T>(ref T item, T value, string name)
        {
            item = value;
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(name));
            }
        }

        #endregion
    }
}

Answer 1

short answer: you can't... updating the datasource automatically updates the display, and that automatically reverts the selection back to the first one in the list. The only other thing you could do would be to remember the selection in memory, then re-select it once the binding is updated, but since you said that's not an option for you, then it's impossible.

Unless you don't mind setting a flag to skip your Select event code...

e.g.:

remember,
update binding
set flag to "skip code"
select item from memory
set flag to "run code"

Answer 2

Try collectionviewsource.view.moveto(-1).