private static void OnIsModalChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ModalContentPresenter control = (ModalContentPresenter)d;
if ((bool)e.NewValue == true)
{
/*
* Cache the keyboard navigation mode of the primary content before setting it to
* 'none' so that it can be restored when the modal content is hidden.
*/
control.cachedTabNavigationMode = KeyboardNavigation.GetTabNavigation(control.primaryContentPresenter);
control.cachedDirectionalNavigationMode = KeyboardNavigation.GetDirectionalNavigation(control.primaryContentPresenter);
control.cachedFocusedElement = Keyboard.FocusedElement;
KeyboardNavigation.SetTabNavigation(control.primaryContentPresenter, KeyboardNavigationMode.None);
KeyboardNavigation.SetDirectionalNavigation(control.primaryContentPresenter, KeyboardNavigationMode.None);
/*
* Show the overlay (which in turn shows the modal content as it is a child of
* the overlay) and move focus to the first logical element.
*/
control.overlay.Visibility = Visibility.Visible;
control.overlay.MoveFocus(traversalDirection);
control.RaiseModalContentShownEvents();
}
else
{
/*
* Hide the overlay (which also hides the modal content...).
*/
control.overlay.Visibility = Visibility.Hidden;
/*
* Restore the cached keyboard navigation value on the primary content and move
* focus to its first logical element.
*/
KeyboardNavigation.SetTabNavigation(control.primaryContentPresenter, control.cachedTabNavigationMode);
KeyboardNavigation.SetDirectionalNavigation(control.primaryContentPresenter, control.cachedDirectionalNavigationMode);
Keyboard.Focus(control.cachedFocusedElement);
control.primaryContentPresenter.MoveFocus(traversalDirection);
control.RaiseModalContentHiddenEvents();
}
}
/// <summary>
/// Gets the focusable descendents of the specified element.
/// </summary>
/// <param name="element">The element.</param>
/// <returns>The element's focusable descendents.</returns>
private static IEnumerable <IInputElement> GetFocusableDescendents(IInputElement element)
{
var mode = KeyboardNavigation.GetDirectionalNavigation((InputElement)element);
var children = element.GetVisualChildren().OfType <IInputElement>();
foreach (var child in children)
{
if (child.CanFocus())
{
yield return(child);
}
if (child.CanFocusDescendents())
{
foreach (var descendent in GetFocusableDescendents(child))
{
yield return(descendent);
}
}
}
}
/// <summary>
/// Gets the next control in the specified navigation direction.
/// </summary>
/// <param name="element">The element.</param>
/// <param name="direction">The navigation direction.</param>
/// <returns>
/// The next element in the specified direction, or null if <paramref name="element"/>
/// was the last in the requested direction.
/// </returns>
public static IInputElement GetNext(
IInputElement element,
FocusNavigationDirection direction)
{
Contract.Requires <ArgumentNullException>(element != null);
Contract.Requires <ArgumentException>(
direction != FocusNavigationDirection.Next &&
direction != FocusNavigationDirection.Previous);
var container = element.GetVisualParent <IInputElement>();
if (container != null)
{
var isForward = IsForward(direction);
var mode = KeyboardNavigation.GetDirectionalNavigation((InputElement)container);
switch (mode)
{
case KeyboardNavigationMode.Continue:
return(GetNextInContainer(element, container, direction) ??
GetFirstInNextContainer(element, direction));
case KeyboardNavigationMode.Cycle:
return(GetNextInContainer(element, container, direction) ??
GetFocusableDescendent(container, direction));
case KeyboardNavigationMode.Contained:
return(GetNextInContainer(element, container, direction));
default:
return(null);
}
}
else
{
return(GetFocusableDescendents(element).FirstOrDefault());
}
}
