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POSlow wpf ItemsControl refresh on ListCollectionView
 

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    <p>The problem I have is my listcollectionview is taking 3-4 seconds to update. I think I have the virtualization configured correctly; however, please point out if it is incorrect. I have my itemssource bound to a ICollectionView.</p> <p>If i set the loop to 3000+ in BindingViewModel UI takes a long time to launch even though it takes less than a second to build the ViewModels. </p> <p>I don't know how to attach files so I'll post all the sample code that reproduces this problem:</p> <p>BigList.Xaml: ` </p> <pre><code> &lt;Style x:Key="textBlockBaseStyle" TargetType="TextBlock"&gt; &lt;Setter Property="Foreground" Value="Blue"/&gt; &lt;/Style&gt; &lt;Style x:Key="headerButtonStyle" TargetType="Button"&gt; &lt;Setter Property="FontWeight" Value="Bold"/&gt; &lt;Setter Property="Foreground" Value="Blue"/&gt; &lt;Setter Property="Background" Value="Transparent" /&gt; &lt;Setter Property="HorizontalContentAlignment" Value="Stretch"/&gt; &lt;Setter Property="BorderBrush" Value="Transparent"/&gt; &lt;Style.Triggers&gt; &lt;Trigger Property="IsMouseOver" Value="True"&gt; &lt;Setter Property="Background" Value="DarkBlue"/&gt; &lt;/Trigger&gt; &lt;/Style.Triggers&gt; &lt;/Style&gt; &lt;Style x:Key="borderBaseStyle" TargetType="Border"&gt; &lt;Setter Property="BorderBrush" Value="Blue"/&gt; &lt;/Style&gt; &lt;!--these two styles let us cascadingly style on the page without having to specify styles apparently styles don't cascade into itemscontrols... in the items control we must reference via key --&gt; &lt;Style TargetType="TextBlock" BasedOn="{StaticResource textBlockBaseStyle}"/&gt; &lt;Style TargetType="Border" BasedOn="{StaticResource borderBaseStyle}"/&gt; &lt;!-- hover styles --&gt; &lt;Style x:Key="onmouseover" TargetType="{x:Type Border}" BasedOn="{StaticResource borderBaseStyle}"&gt; &lt;Style.Triggers&gt; &lt;Trigger Property="IsMouseOver" Value="True"&gt; &lt;Setter Property="Background" Value="DarkBlue"/&gt; &lt;/Trigger&gt; &lt;/Style.Triggers&gt; &lt;/Style&gt; &lt;/UserControl.Resources&gt; &lt;Grid&gt; &lt;StackPanel Width="390"&gt; &lt;!-- Header--&gt; &lt;Border BorderThickness="1,1,1,1"&gt; &lt;Grid&gt; &lt;Grid.ColumnDefinitions&gt; &lt;ColumnDefinition Width="55"/&gt; &lt;ColumnDefinition Width="70"/&gt; &lt;ColumnDefinition Width="70"/&gt; &lt;ColumnDefinition Width="70"/&gt; &lt;ColumnDefinition Width="70"/&gt; &lt;/Grid.ColumnDefinitions&gt; &lt;Button Command="{Binding SortFirstNameCommand}" Style="{StaticResource headerButtonStyle}" Grid.Column="1" &gt; &lt;TextBlock TextAlignment="Left" Text="First"/&gt; &lt;/Button&gt; &lt;Button Style="{StaticResource headerButtonStyle}" Grid.Column="2" &gt; &lt;TextBlock TextAlignment="Left" Text="Last"/&gt; &lt;/Button&gt; &lt;Button Style="{StaticResource headerButtonStyle}" Grid.Column="3" &gt; &lt;TextBlock TextAlignment="Left" Text="Activity"/&gt; &lt;/Button&gt; &lt;Button Style="{StaticResource headerButtonStyle}" Grid.Column="4"&gt; &lt;TextBlock TextAlignment="Left" Text="Last Activity"/&gt; &lt;/Button&gt; &lt;/Grid&gt; &lt;/Border&gt; &lt;Border BorderThickness="1,0,1,1"&gt; &lt;ItemsControl VirtualizingStackPanel.IsVirtualizing="True" VirtualizingStackPanel.VirtualizationMode="Recycling" ItemsSource="{Binding UsersAvailForEmail}" MaxHeight="400"&gt; &lt;ItemsControl.Template&gt; &lt;ControlTemplate&gt; &lt;ScrollViewer x:Name="ScrollViewer" HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto" IsDeferredScrollingEnabled="True" Padding="{TemplateBinding Padding}"&gt; &lt;ItemsPresenter/&gt; &lt;/ScrollViewer&gt; &lt;/ControlTemplate&gt; &lt;/ItemsControl.Template&gt; &lt;ItemsControl.ItemTemplate&gt; &lt;DataTemplate&gt; &lt;Border Style="{StaticResource onmouseover}" BorderThickness="0,0,1,1"&gt; &lt;CheckBox Margin="20,5" IsChecked="{Binding IsSelected}"&gt; &lt;CheckBox.Content&gt; &lt;StackPanel Orientation="Horizontal"&gt; &lt;TextBlock Width="20"/&gt; &lt;TextBlock Width="70" Style="{StaticResource textBlockBaseStyle}" Grid.Column="1" Text="{Binding FirstName}"/&gt; &lt;TextBlock Width="70" Style="{StaticResource textBlockBaseStyle}" Grid.Column="2" Text="{Binding LastName}"/&gt; &lt;TextBlock Width="70" Style="{StaticResource textBlockBaseStyle}" Grid.Column="3" Text="{Binding Action}"/&gt; &lt;TextBlock Width="60" Style="{StaticResource textBlockBaseStyle}" Grid.Column="4" Text="{Binding ActionId}"/&gt; &lt;/StackPanel&gt; &lt;/CheckBox.Content&gt; &lt;/CheckBox&gt; &lt;/Border&gt; &lt;/DataTemplate&gt; &lt;/ItemsControl.ItemTemplate&gt; &lt;/ItemsControl&gt; &lt;/Border&gt; &lt;/StackPanel&gt; &lt;/Grid&gt; </code></pre> <p> `</p> <p>BindingViewModel.cs:</p> <pre><code>using System.Linq; using System.Text; using System.ComponentModel; using System.Collections.ObjectModel; using System.Windows.Data; namespace LargeItemsCollection { public class BindingViewModel : INotifyPropertyChanged { ObservableCollection&lt;EmailPersonViewModel&gt; _usersAvail = new ObservableCollection&lt;EmailPersonViewModel&gt;(); ListCollectionView _lvc = null; public BindingViewModel() { for (int i = 0; i &lt; 4000; i++) { _usersAvail.Add( new EmailPersonViewModel { FirstName = "f" +i.ToString() , LastName= "l" + i.ToString(), Action= "a" + i.ToString(), ActionId="ai" + i.ToString(), IsSelected=true }); } _lvc = new ListCollectionView(_usersAvail); } public ICollectionView UsersAvailForEmail { get { return _lvc; } } /// &lt;summary&gt; /// Raised when a property on this object has a new value. /// &lt;/summary&gt; public event PropertyChangedEventHandler PropertyChanged; /// &lt;summary&gt; /// Raises this object's PropertyChanged event. /// &lt;/summary&gt; /// &lt;param name="propertyName"&gt;The property that has a new value.&lt;/param&gt; public virtual void OnPropertyChanged(string propertyName) { PropertyChangedEventHandler handler = this.PropertyChanged; if (handler != null) { var e = new PropertyChangedEventArgs(propertyName); handler(this, e); } } } </code></pre> <p>EmailPersonViewModel.cs:</p> <pre><code>using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace LargeItemsCollection { public class EmailPersonViewModel { public string FirstName { get; set; } public string LastName { get; set; } public string Action { get; set; } public string ActionId { get; set; } public bool IsSelected { get; set; } public EmailPersonViewModel() { } } } </code></pre> <p>MainWindow.xaml:</p> <pre><code>&lt;Window x:Class="LargeItemsCollection.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:LargeItemsCollection" Title="MainWindow" Height="350" Width="525"&gt; &lt;Grid&gt; &lt;local:BigList/&gt; &lt;/Grid&gt; &lt;/Window&gt; </code></pre> <p>MainWindow.cs:</p> <pre><code>using System; using System.Collections.Generic; using System.Linq; using System.Text; 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; namespace LargeItemsCollection { /// &lt;summary&gt; /// Interaction logic for MainWindow.xaml /// &lt;/summary&gt; public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); DataContext = new BindingViewModel(); } } } </code></pre>
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