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    copied!<p>There's actually much more to it than just making the <code>ItemsPanelTemplate</code> use <code>VirtualizingStackPanel</code>. The default <code>ControlTemplate</code> for <code>ItemsControl</code> does not have a <code>ScrollViewer</code>, which is the key to virtualization. Adding to the the default control template for <code>ItemsControl</code> (using the control template for <code>ListBox</code> as a template) gives us the following: </p> <pre><code>&lt;ItemsControl VirtualizingStackPanel.IsVirtualizing="True" ScrollViewer.CanContentScroll="True" ItemsSource="{Binding Path=AccountViews.Tables[0]}"&gt; &lt;ItemsControl.ItemTemplate&gt; &lt;DataTemplate&gt; &lt;TextBlock Initialized="TextBlock_Initialized" Text="{Binding Path=Name}" /&gt; &lt;/DataTemplate&gt; &lt;/ItemsControl.ItemTemplate&gt; &lt;ItemsControl.ItemsPanel&gt; &lt;ItemsPanelTemplate&gt; &lt;VirtualizingStackPanel /&gt; &lt;/ItemsPanelTemplate&gt; &lt;/ItemsControl.ItemsPanel&gt; &lt;ItemsControl.Template&gt; &lt;ControlTemplate&gt; &lt;Border BorderThickness="{TemplateBinding Border.BorderThickness}" Padding="{TemplateBinding Control.Padding}" BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" SnapsToDevicePixels="True"&gt; &lt;ScrollViewer Padding="{TemplateBinding Control.Padding}" Focusable="False"&gt; &lt;ItemsPresenter SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" /&gt; &lt;/ScrollViewer&gt; &lt;/Border&gt; &lt;/ControlTemplate&gt; &lt;/ItemsControl.Template&gt; &lt;/ItemsControl&gt; </code></pre> <p>(BTW, a great tool for looking at default control templates is <a href="http://www.sellsbrothers.com/Posts/Details/2091" rel="noreferrer">Show Me The Template</a>)</p> <p>Things to notice:</p> <p>You have to set <code>ScrollViewer.CanContentScroll="True"</code>, see <a href="https://stackoverflow.com/questions/1924089/listbox-virtualizingstackpanel-and-smooth-scrolling-in-wpf">here</a> for why.</p> <p>Also notice that I put <code>VirtualizingStackPanel.VirtualizationMode="Recycling"</code>. This will reduce the numbers of times <code>TextBlock_Initialized</code> is called to however many TextBlocks are visible on the screen. You can read more on UI virtualization <a href="https://web.archive.org/web/20150708100804/http://www.zagstudio.com:80/blog/497" rel="noreferrer">here </a>.</p> <p>EDIT: Forgot to state the obvious: as an alternate solution, you can just replace <code>ItemsControl</code> with <code>ListBox</code> :) Also, check out this <a href="https://msdn.microsoft.com/en-us/library/vstudio/cc716879(v=vs.100).aspx" rel="noreferrer">Optimizing Performance on MSDN page</a> and notice that <code>ItemsControl</code> isn't in the "Controls That Implement Performance Features" table, which is why we need to edit the control template.</p>
 

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