/// <summary>
/// Raises an DropDownClosing event when the IsDropDownOpen property is
/// changing from true to false.
/// </summary>
/// <param name="e">
/// Provides any observers the opportunity to cancel the operation
/// and halt closing the drop down.
/// </param>
protected virtual void OnDropDownClosing(RoutedPropertyChangingEventArgs <bool> e)
{
RoutedPropertyChangingEventHandler <bool> handler = DropDownClosing;
if (handler != null)
{
handler(this, e);
}
}
/// <summary>
/// IsDropDownOpenProperty property changed handler.
/// </summary>
/// <param name="d">AutoCompleteTextBox that changed its IsDropDownOpen.</param>
/// <param name="e">Event arguments.</param>
private static void OnIsDropDownOpenPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
AutoCompleteTextBox source = d as AutoCompleteTextBox;
// Ignore the change if requested
if (source.IgnorePropertyChange)
{
source.IgnorePropertyChange = false;
return;
}
bool oldValue = (bool)e.OldValue;
bool newValue = (bool)e.NewValue;
bool delayedClosingVisual = source.PopupClosedVisualState;
RoutedPropertyChangingEventArgs <bool> args = new RoutedPropertyChangingEventArgs <bool>(e.Property, oldValue, newValue, true);
AutoCompleteBoxAutomationPeer peer = FrameworkElementAutomationPeer.FromElement(source) as AutoCompleteBoxAutomationPeer;
if (peer != null)
{
peer.RaiseExpandCollapseAutomationEvent(oldValue, newValue);
}
if (newValue)
{
// Opening
source.OnDropDownOpening(args);
// Opened
if (!args.Cancel)
{
source.OpenDropDown(oldValue, newValue);
}
}
else
{
// Closing
source.OnDropDownClosing(args);
if (source.View == null || source.View.Count == 0)
{
delayedClosingVisual = false;
}
// Immediately close the drop down window:
// When a popup closed visual state is present, the code path is
// slightly different and the actual call to CloseDropDown will
// be called only after the visual state's transition is done
if (!args.Cancel && !delayedClosingVisual)
{
source.CloseDropDown(oldValue, newValue);
}
}
// If canceled, revert the value change
if (args.Cancel)
{
source.IgnorePropertyChange = true;
source.SetValue(e.Property, oldValue);
}
// Closing call when visual states are in use
if (delayedClosingVisual)
{
source.UpdateVisualState(true);
}
}