Items controls, collections and virtualization

ListBox, ListView, DataGrid and ItemsControl, item containers and templates, grouping and sorting with CollectionViewSource, and the virtualization settings that decide whether a list stays smooth.

Choosing an items control

Control	Gives you	Pick it for
`ItemsControl`	Just repeated items	A toolbar or a badge strip with no selection
`ListBox`	Selection, keyboard navigation, containers	A single-select list of anything
`ListView`	A `GridView` of columns	A lightweight table
`DataGrid`	Editing, sorting, column sizing, row details	Tabular data the user edits
`TreeView`	Hierarchy with expand and collapse	Nested categories

<ListBox ItemsSource="{Binding Orders}"
         SelectedItem="{Binding SelectedOrder}"
         ScrollViewer.CanContentScroll="True"
         VirtualizingPanel.IsVirtualizing="True"
         VirtualizingPanel.VirtualizationMode="Recycling">
  <ListBox.ItemTemplate>
    <DataTemplate DataType="{x:Type models:Order}">
      <Grid Margin="4">
        <Grid.ColumnDefinitions>
          <ColumnDefinition Width="80" />
          <ColumnDefinition Width="*" />
          <ColumnDefinition Width="Auto" />
        </Grid.ColumnDefinitions>
        <TextBlock Grid.Column="0" Text="{Binding Id}" />
        <TextBlock Grid.Column="1" Text="{Binding Customer}" TextTrimming="CharacterEllipsis" />
        <TextBlock Grid.Column="2" Text="{Binding Total, StringFormat={}{0:C}}" />
      </Grid>
    </DataTemplate>
  </ListBox.ItemTemplate>
</ListBox>

ScrollViewer.CanContentScroll="True" is what enables item-based virtualisation; setting it to false switches to pixel scrolling and disables virtualisation entirely.
VirtualizationMode="Recycling" reuses containers instead of creating new ones, which matters when the item template is expensive.
Never put a ScrollViewer around a virtualising list. It measures the list at full height, every item is realised, and the optimisation is gone.

Grouping, sorting and filtering

var view = CollectionViewSource.GetDefaultView(Orders);
view.SortDescriptions.Add(new SortDescription(nameof(Order.Date), ListSortDirection.Descending));
view.GroupDescriptions.Add(new PropertyGroupDescription(nameof(Order.Region)));

view.Filter = o => ((Order)o).Total >= _minTotal;

// a filter change must be announced or the view looks frozen
view.Refresh();

// and the collection itself must notify for the view to follow
public ObservableCollection<Order> Orders { get; } = new();

<ListBox ItemsSource="{Binding Orders}">
  <ListBox.GroupStyle>
    <GroupStyle>
      <GroupStyle.HeaderTemplate>
        <DataTemplate>
          <TextBlock FontWeight="Bold" Margin="0,8,0,2"
                     Text="{Binding Name}" />
        </DataTemplate>
      </GroupStyle.HeaderTemplate>
    </GroupStyle>
  </ListBox.GroupStyle>
</ListBox>

The default view is shared per collection. If two independent controls must filter the same source differently, wrap each in its own CollectionViewSource - otherwise clearing the filter in one panel silently changes the other.

Staying smooth

// batch changes so the UI updates once instead of once per item
using (Orders.DeferRefresh())
{
    foreach (var order in loaded)
        Orders.Add(order);
}

// when the list is rebuilt often, hand over a finished collection instead
OnPropertyChanged(nameof(Orders));

<!-- virtualisation settings belong in the item container style, set once -->
<Style TargetType="ListBoxItem">
  <Setter Property="VirtualizingPanel.IsVirtualizing" Value="True" />
  <Setter Property="VirtualizingPanel.VirtualizationMode" Value="Recycling" />
</Style>

Symptom	Likely cause	Fix
Slow scroll with 5,000 rows	A `ScrollViewer` outside the list	Remove it; let the list scroll itself
Memory grows while scrolling	Virtualization disabled by grouping	WPF cannot virtualise grouped lists - use paging
Choppy updates while loading	One `Add` per item with notifications on	`DeferRefresh` or build the list off-thread then assign
Rows show stale data	Model has no `INotifyPropertyChanged`	Implement it, or replace the item in the collection
Selection jumps on refresh	View refresh resets the current item	Capture the key before `Refresh` and restore after

⚠️

Grouping and virtualisation are mutually exclusive in WPF. If you need both, use explicit paging or build the grouping into the data and page over the groups - enabling grouping on a 100,000-row list will hang the application.

FAQ

ObservableCollection or a custom collection?

ObservableCollection<T> covers almost every case. Reach for a custom implementation only when you need batched notifications, and add a Reset style notification rather than thousands of individual ones.

Why does binding to a plain List work but not update?

A plain list is readable but not observable. WPF renders it once. Replace it with ObservableCollection<T> or reassign the property and raise PropertyChanged.

Resources, styles, templates and themes WPF performance and testing MVVM applications

Last refreshed 2026-09-18.

Items controls, collections and virtualization

Choosing an items control

Grouping, sorting and filtering

Staying smooth

FAQ

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