/// <summary>
/// Coerce Callback method of the SelectedIndex Dependency Property.
/// </summary>
/// <param name="sender">The instance of the class of which the SelectedIndex property is about to change.</param>
/// <param name="value">The proposed new value for the SelectedIndex property.</param>
/// <returns>The actual new value for the SelectedIndex property.</returns>
private static object CoerceSelectedIndex(DependencyObject sender, object value)
{
PageViewer subject = (PageViewer)sender;
int newValue = (int)value;
if (newValue < -1 || newValue > subject.Items.Count - 1)
{
return(-1);
}
return(value);
}
/// <summary>
/// Property Changed Callback method of the Items Dependency Property.
/// </summary>
/// <param name="sender">The instance of the class that had the Items property changed.</param>
/// <param name="e">The <see cref="System.Windows.DependencyPropertyChangedEventArgs"/> instance containing the event data.</param>
private static void OnItemsChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
PageViewer subject = (PageViewer)sender;
ObservableCollection <PageViewerItem> newValue = (ObservableCollection <PageViewerItem>)e.NewValue;
ObservableCollection <PageViewerItem> oldValue = (ObservableCollection <PageViewerItem>)e.OldValue;
if (oldValue != null)
{
oldValue.CollectionChanged -= subject.Items_CollectionChanged;
subject.SetOldItemsOwner(oldValue);
}
if (newValue != null)
{
newValue.CollectionChanged += subject.Items_CollectionChanged;
subject.SetNewItemsOwner(newValue);
}
}
/// <summary>
/// Property Changed Callback method of the SelectedItem Dependency Property.
/// </summary>
/// <param name="sender">The instance of the class that had the SelectedItem property changed.</param>
/// <param name="e">The <see cref="System.Windows.DependencyPropertyChangedEventArgs"/> instance containing the event data.</param>
private static void OnSelectedItemChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
PageViewer subject = (PageViewer)sender;
PageViewerItem newValue = (PageViewerItem)e.NewValue;
PageViewerItem oldValue = (PageViewerItem)e.OldValue;
subject.IsSettingSelection = true;
if (oldValue != null)
{
oldValue.FreeContent();
oldValue.IsSelected = false;
}
if (newValue != null)
{
newValue.InitializeContent();
newValue.IsSelected = true;
}
subject.IsSettingSelection = false;
}