/// <summary>
/// Gets the focusable descendants of the specified element.
/// </summary>
/// <param name="element">The element.</param>
/// <param name="direction">The tab direction. Must be Next or Previous.</param>
/// <returns>The element's focusable descendants.</returns>
private static IEnumerable <IInputElement> GetFocusableDescendants(IInputElement element,
NavigationDirection direction)
{
var mode = KeyboardNavigation.GetTabNavigation((InputElement)element);
if (mode == KeyboardNavigationMode.None)
{
yield break;
}
var children = element.GetVisualChildren().OfType <IInputElement>();
if (mode == KeyboardNavigationMode.Once)
{
var active = KeyboardNavigation.GetTabOnceActiveElement((InputElement)element);
if (active != null)
{
yield return(active);
yield break;
}
else
{
children = children.Take(1);
}
}
foreach (var child in children)
{
var customNext = GetCustomNext(child, direction);
if (customNext.handled)
{
yield return(customNext.next);
}
else
{
if (child.CanFocus() && KeyboardNavigation.GetIsTabStop((InputElement)child))
{
yield return(child);
}
if (child.CanFocusDescendants())
{
foreach (var descendant in GetFocusableDescendants(child, direction))
{
if (KeyboardNavigation.GetIsTabStop((InputElement)descendant))
{
yield return(descendant);
}
}
}
}
}
}
/// <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.GetTabNavigation((InputElement)element);
if (mode == KeyboardNavigationMode.None)
{
yield break;
}
var children = element.GetVisualChildren().OfType <IInputElement>();
if (mode == KeyboardNavigationMode.Once)
{
var active = KeyboardNavigation.GetTabOnceActiveElement((InputElement)element);
if (active != null)
{
yield return(active);
yield break;
}
else
{
children = children.Take(1);
}
}
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 focusable descendants of the specified element.
/// </summary>
/// <param name="element">The element.</param>
/// <returns>The element's focusable descendants.</returns>
private static IEnumerable <IInputElement> GetFocusableDescendants(IInputElement element)
{
var children = element.GetVisualChildren().OfType <IInputElement>();
foreach (var child in children)
{
if (child.CanFocus())
{
yield return(child);
}
if (child.CanFocusDescendants())
{
foreach (var descendant in GetFocusableDescendants(child))
{
yield return(descendant);
}
}
}
}
/// <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 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 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.GetTabNavigation((InputElement)element);
if (mode == KeyboardNavigationMode.None)
{
yield break;
}
var children = element.GetVisualChildren().OfType<IInputElement>();
if (mode == KeyboardNavigationMode.Once)
{
var active = KeyboardNavigation.GetTabOnceActiveElement((InputElement)element);
if (active != null)
{
yield return active;
yield break;
}
else
{
children = children.Take(1);
}
}
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 previous item that should be focused in the specified container.
/// </summary>
/// <param name="element">The starting element/</param>
/// <param name="container">The container.</param>
/// <returns>The previous element, or null if the element is the first.</returns>
private static IInputElement GetPreviousInContainer(IInputElement element, IInputElement container)
{
return container.GetVisualChildren()
.OfType<IInputElement>()
.Where(CanFocus)
.TakeWhile(x => x != element)
.LastOrDefault();
}
/// <summary>
/// Gets the next item that should be focused in the specified container.
/// </summary>
/// <param name="element">The starting element/</param>
/// <param name="container">The container.</param>
/// <returns>The next element, or null if the element is the last.</returns>
private static IInputElement GetNextInContainer(IInputElement element, IInputElement container)
{
var descendent = GetDescendents(element).FirstOrDefault();
if (descendent != null)
{
return descendent;
}
else if (container != null)
{
var sibling = container.GetVisualChildren()
.OfType<IInputElement>()
.Where(CanFocus)
.SkipWhile(x => x != element)
.Skip(1)
.FirstOrDefault();
if (sibling != null)
{
return sibling;
}
}
return null;
}
/// <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 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;
}
}
}
}