mvvm how to make a list view auto scroll to a new Item in a list view

This solution is for a ListBox, but it could be modified for a ListView… This will scroll the selected item into view when you change the selected item from the ViewModel.

Class:

/// <summary>
/// ListBoxItem Behavior class
/// </summary>
public static class ListBoxItemBehavior
{
    #region IsBroughtIntoViewWhenSelected

    /// <summary>
    /// Gets the IsBroughtIntoViewWhenSelected value
    /// </summary>
    /// <param name="listBoxItem"></param>
    /// <returns></returns>
    public static bool GetIsBroughtIntoViewWhenSelected(ListBoxItem listBoxItem)
    {
        return (bool)listBoxItem.GetValue(IsBroughtIntoViewWhenSelectedProperty);
    }

    /// <summary>
    /// Sets the IsBroughtIntoViewWhenSelected value
    /// </summary>
    /// <param name="listBoxItem"></param>
    /// <param name="value"></param>
    public static void SetIsBroughtIntoViewWhenSelected(
      ListBoxItem listBoxItem, bool value)
    {
        listBoxItem.SetValue(IsBroughtIntoViewWhenSelectedProperty, value);
    }

    /// <summary>
    /// Determins if the ListBoxItem is bought into view when enabled
    /// </summary>
    public static readonly DependencyProperty IsBroughtIntoViewWhenSelectedProperty =
        DependencyProperty.RegisterAttached(
        "IsBroughtIntoViewWhenSelected",
        typeof(bool),
        typeof(ListBoxItemBehavior),
        new UIPropertyMetadata(false, OnIsBroughtIntoViewWhenSelectedChanged));

    /// <summary>
    /// Action to take when item is brought into view
    /// </summary>
    /// <param name="depObj"></param>
    /// <param name="e"></param>
    static void OnIsBroughtIntoViewWhenSelectedChanged(
      DependencyObject depObj, DependencyPropertyChangedEventArgs e)
    {
        ListBoxItem item = depObj as ListBoxItem;
        if (item == null)
            return;

        if (e.NewValue is bool == false)
            return;

        if ((bool)e.NewValue)
            item.Selected += OnListBoxItemSelected;
        else
            item.Selected -= OnListBoxItemSelected;
    }

    static void OnListBoxItemSelected(object sender, RoutedEventArgs e)
    {
        // Only react to the Selected event raised by the ListBoxItem 
        // whose IsSelected property was modified.  Ignore all ancestors 
        // who are merely reporting that a descendant's Selected fired. 
        if (!Object.ReferenceEquals(sender, e.OriginalSource))
            return;

        ListBoxItem item = e.OriginalSource as ListBoxItem;
        if (item != null)
            item.BringIntoView();
    }

    #endregion // IsBroughtIntoViewWhenSelected
}

Add the xmlns to your view:

xmlns:util="clr-namespace:YourNamespaceHere.Classes"

Add the style to the resources of the Window/UserControl:

<Window.Resources>
    <Style x:Key="ListBoxItemContainerStyle" TargetType="{x:Type ListBoxItem}"
        BasedOn="{StaticResource {x:Type ListBoxItem}}">
        <Setter Property="util:ListBoxItemBehavior.IsBroughtIntoViewWhenSelected" Value="true"/>
    </Style>
</Window.Resources>

Implement the listbox:

<ListBox ItemsSource="{Binding MyView}"
         DisplayMemberPath="Title"
         SelectedItem="{Binding SelectedItem}" 
         ItemContainerStyle="{StaticResource ListBoxItemContainerStyle}"/>

Leave a Comment