CollectionViewSource is a proxy for a CollectionView class, or a class derived from CollectionView. CollectionViewSource enables XAML code to set the commonly used CollectionView properties, passing these settings to the underlying view. CollectionViewSource has a View property that holds the actual view and a Source property that holds the source collection.

You can think of a collection view as the layer on top of the binding source collection that allows you to navigate and display the collection based on sort, filter, and group queries, all without having to manipulate the underlying source collection itself. If the source collection implements the INotifyCollectionChanged interface, the changes raised by the CollectionChanged event are propagated to the views.

Because views do not change the underlying source collections, each source collection can have multiple views associated with it. For example, you may have a collection of Task objects. With the use of views, you can display that same data in different ways. For example, on the left side of your page you may want to show tasks sorted by priority, and on the right side, grouped by area.

For more information, see the Binding to Collections section in the Data Binding Overview.

This example shows how to create a view of a data collection in Extensible Application Markup Language (XAML). Views allow for the functionalities of grouping, sorting, filtering, and the notion of a current item.

In the following example, the static resource named places is defined as a collection of Place objects, in which each Place object is consisted of a city name and the state. The prefix src is mapped to the namespace where the data source Places is defined. The prefix scm and dat are mapped to the System.ComponentModel and System.Windows.Data namespaces respectively.

The following example creates a view of the data collection that is sorted by the city name and grouped by the state.

<Window.Resources>

  <src:Places x:Key="places"/>

  <CollectionViewSource Source="{StaticResource places}" x:Key="cvs">
    <CollectionViewSource.SortDescriptions>
      <scm:SortDescription PropertyName="CityName"/>
    </CollectionViewSource.SortDescriptions>
    <CollectionViewSource.GroupDescriptions>
      <dat:PropertyGroupDescription PropertyName="State"/>
    </CollectionViewSource.GroupDescriptions>
  </CollectionViewSource>

The view can then be a binding source, as in the following example:

<ListBox ItemsSource="{Binding Source={StaticResource cvs}}"
         DisplayMemberPath="CityName" Name="lb">
  <ListBox.GroupStyle>
    <x:Static Member="GroupStyle.Default"/>
  </ListBox.GroupStyle>
</ListBox>

For bindings to XML data defined in an XmlDataProvider resource, precede the XML name with an @ symbol.

<XmlDataProvider x:Key="myTasks" XPath="Tasks/Task">
    <x:XData>
        <Tasks xmlns="">
            <Task Name="Groceries" Priority="2" Type="Home">

<CollectionViewSource x:Key="mySortedTasks"
                      Source="{StaticResource myTasks}">
    <CollectionViewSource.SortDescriptions>
        <scm:SortDescription PropertyName="@Priority" />
    </CollectionViewSource.SortDescriptions>
    <CollectionViewSource.GroupDescriptions>
        <dat:PropertyGroupDescription PropertyName="@Priority" />
    </CollectionViewSource.GroupDescriptions>
</CollectionViewSource>

To see the entire example, please see Sorting and Grouping Data in XAML Sample.

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

.NET Framework

Reference

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