CurrentChangingEventArgs Class

Definition

/// [Windows.Foundation.Metadata.ContractVersion(Windows.Foundation.UniversalApiContract, 65536)]
/// [Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
/// [Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
class CurrentChangingEventArgs

[Windows.Foundation.Metadata.ContractVersion(typeof(Windows.Foundation.UniversalApiContract), 65536)]
[Windows.Foundation.Metadata.MarshalingBehavior(Windows.Foundation.Metadata.MarshalingType.Agile)]
[Windows.Foundation.Metadata.Threading(Windows.Foundation.Metadata.ThreadingModel.Both)]
public class CurrentChangingEventArgs

Public Class CurrentChangingEventArgs

Inheritance

Object IInspectable CurrentChangingEventArgs

Attributes

ContractVersionAttribute MarshalingBehaviorAttribute ThreadingAttribute

Windows requirements

Examples

The following code example demonstrates how to handle the CurrentChanging event. In this example, the XAML shows the content of a page with a GridView bound to a CollectionViewSource. The code-behind shows the CollectionViewSource initialization, which includes setting its Source and retrieving its View in order to attach the CurrentChanging event handler.

<Page.Resources>
  <CollectionViewSource x:Name="cvs" />
  <DataTemplate x:Key="myDataTemplate">
    <Border Background="#FF939598" Width="200" Height="200">
      <TextBlock Text="{Binding Path=Name}" />
    </Border>
  </DataTemplate>
</Page.Resources>

<Grid Background="{StaticResource ApplicationPageBackgroundBrush}">
  <GridView x:Name="PicturesGrid" 
    SelectionMode="Single" CanReorderItems="False" CanDragItems="False"
    ItemsSource="{Binding Source={StaticResource cvs}}"                
    ItemTemplate="{StaticResource myDataTemplate}" >
    <GridView.ItemsPanel>
      <ItemsPanelTemplate>
        <WrapGrid VerticalChildrenAlignment="Top" 
          HorizontalChildrenAlignment="Left" />
      </ItemsPanelTemplate>
    </GridView.ItemsPanel>
  </GridView>
</Grid>

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    var library = Windows.Storage.KnownFolders.PicturesLibrary;
    var queryOptions = new Windows.Storage.Search.QueryOptions();
    queryOptions.FolderDepth = Windows.Storage.Search.FolderDepth.Deep;
    queryOptions.IndexerOption = 
        Windows.Storage.Search.IndexerOption.UseIndexerWhenAvailable;

    var fileQuery = library.CreateFileQueryWithOptions(queryOptions);

    var fif = new Windows.Storage.BulkAccess.FileInformationFactory(
        fileQuery, 
        Windows.Storage.FileProperties.ThumbnailMode.PicturesView, 190, 
        Windows.Storage.FileProperties.ThumbnailOptions.UseCurrentScale, 
        false);

    var dataSource = fif.GetVirtualizedFilesVector();
    cvs.Source = dataSource;
    cvs.View.CurrentChanging += View_CurrentChanging;
}

private void View_CurrentChanging(object sender, CurrentChangingEventArgs e)
{
    Debug.WriteLine("Cancel = " + e.Cancel);
    Debug.WriteLine("IsCancelable = " + e.IsCancelable);
    if (e.IsCancelable == true)
    {
        // Cancel the change. The previously selected item remains selected.
        e.Cancel = true;
    }
}

Remarks

The CurrentChanging event occurs when the CurrentItem property value changes in an ICollectionView implementation. The ICollectionView implementation uses the CurrentChangingEventArgs constructor to specify whether you can cancel the CurrentItem change in a CurrentChanging event handler. If the IsCancelable property value is true, you can cancel the CurrentItem change by setting the Cancel property to true. Otherwise, you cannot cancel the CurrentItem change.

Constructors

Properties

Applies to

See also

• XAML data binding sample
• Data binding in depth