/// <summary>
/// Puts focus to some other block.
/// </summary>
/// <returns>true if successful, false if the method had no effect</returns>
/// <remarks>Normally called before deleting a block.</remarks>
public bool RemoveFocus(MoveFocusDirection direction)
{
Block neighbour = null;
if (direction == MoveFocusDirection.SelectPrev ||
direction == MoveFocusDirection.SelectPrevInChain)
{
if (direction == MoveFocusDirection.SelectPrev)
{
neighbour = this.FindPrevFocusableBlock();
}
else
{
neighbour = this.FindPrevFocusableBlockInChain();
}
if (neighbour == null)
{
// if there is no prev block,
// try to select next block
neighbour = this.FindNextFocusableBlock();
}
}
else if (direction == MoveFocusDirection.SelectNext ||
direction == MoveFocusDirection.SelectNextInChain)
{
if (direction == MoveFocusDirection.SelectNext)
{
neighbour = this.FindNextFocusableBlock();
}
else
{
neighbour = this.FindNextFocusableBlockInChain();
}
if (neighbour == null)
{
// if there is no next block,
// try to select previous block
neighbour = this.FindPrevFocusableBlock();
}
}
if (neighbour == null)
{
// if toRemoveFocusFrom is the only block,
// try to select parent
neighbour = this.FindNearestFocusableParent();
}
if (neighbour != null)
{
// if found someone, select it
neighbour.SetFocus();
}
return(neighbour != null);
}
protected bool AlignedPanelMoveFocus1(MoveFocusDirection direction)
{
FrameworkElement currentElement = GetFocusedElementOrChild();
if (currentElement == null)
{
return(false);
}
RectangleF currentFocusRect = currentElement.ActualBounds;
ICollection <FrameworkElement> focusableChildren = new List <FrameworkElement>();
AlignedPanelAddPotentialFocusNeighbors(currentFocusRect, focusableChildren, true);
// Check child controls
if (focusableChildren.Count == 0)
{
return(false);
}
FrameworkElement nextElement = FindNextFocusElement(focusableChildren, currentFocusRect, direction);
return(nextElement != null && nextElement.TrySetFocus(true));
}
/// <summary>
/// Moves the focus from the currently focused element in the screen to our last child in the given
/// direction. For example if <c>direction == MoveFocusDirection.Up</c>, this method tries to focus the
/// topmost child.
/// </summary>
/// <param name="direction">Direction to move the focus.</param>
/// <returns><c>true</c>, if the focus could be moved to the desired child, else <c>false</c>.</returns>
protected bool MoveFocusN(MoveFocusDirection direction)
{
FrameworkElement currentElement = GetFocusedElementOrChild();
if (currentElement == null)
return false;
ICollection<FrameworkElement> focusableChildren = GetFEChildren();
if (focusableChildren.Count == 0)
return false;
FrameworkElement nextElement;
while ((nextElement = FindNextFocusElement(focusableChildren, currentElement.ActualBounds, direction)) != null)
currentElement = nextElement;
return currentElement.TrySetFocus(true);
}
/// <summary>
/// Moves the focus from the currently focused element in the screen to the first child element in the given
/// direction.
/// </summary>
/// <param name="direction">Direction to move the focus.</param>
/// <returns><c>true</c>, if the focus could be moved to the desired child, else <c>false</c>.</returns>
protected bool MoveFocus1(MoveFocusDirection direction)
{
FrameworkElement currentElement = GetFocusedElementOrChild();
if (currentElement == null)
return false;
FrameworkElement nextElement = PredictFocus(currentElement.ActualBounds, direction);
if (nextElement == null) return false;
return nextElement.TrySetFocus(true);
}
/// <summary>
/// Searches through a collection of elements to find the best matching next focus element.
/// </summary>
/// <param name="potentialNextFocusElements">Collection of elements to search.</param>
/// <param name="currentFocusRect">Bounds of the element which currently has focus.</param>
/// <param name="dir">Direction to move the focus.</param>
/// <returns>Next focusable element in the given <paramref name="dir"/> or <c>null</c>, if the given
/// <paramref name="potentialNextFocusElements"/> don't contain a focusable element in the given direction.</returns>
protected static FrameworkElement FindNextFocusElement(IEnumerable<FrameworkElement> potentialNextFocusElements,
RectangleF? currentFocusRect, MoveFocusDirection dir)
{
FrameworkElement bestMatch = null;
float bestDistance = float.MaxValue;
float bestCenterDistance = float.MaxValue;
float bestTopOrLeftDifference = float.MaxValue;
if (!currentFocusRect.HasValue)
return null;
foreach (FrameworkElement child in potentialNextFocusElements)
{
float topOrLeftDifference;
if ((dir == MoveFocusDirection.Up && child.LocatedAbove(currentFocusRect.Value, out topOrLeftDifference)) ||
(dir == MoveFocusDirection.Down && child.LocatedBelow(currentFocusRect.Value, out topOrLeftDifference)) ||
(dir == MoveFocusDirection.Left && child.LocatedLeftOf(currentFocusRect.Value, out topOrLeftDifference)) ||
(dir == MoveFocusDirection.Right && child.LocatedRightOf(currentFocusRect.Value, out topOrLeftDifference)))
{ // Calculate and compare distances of all matches
float centerDistance = CenterDistance(child.ActualBounds, currentFocusRect.Value);
if (centerDistance == 0)
// If the child's center is exactly the center of the currently focused element,
// it won't be used as next focus element
continue;
float distance = BorderDistance(child.ActualBounds, currentFocusRect.Value);
if (bestMatch == null || (distance < bestDistance && topOrLeftDifference < 0)
|| (topOrLeftDifference < bestTopOrLeftDifference && (distance == bestDistance || bestTopOrLeftDifference >= 0))
/*|| topOrLeftDifference == bestTopOrLeftDifference && centerDistance < bestCenterDistance*/)
{
bestMatch = child;
bestDistance = distance;
bestCenterDistance = centerDistance;
bestTopOrLeftDifference = topOrLeftDifference;
}
}
}
return bestMatch;
}
/// <summary>
/// Predicts the next control located inside this element which is positioned in the specified direction
/// <paramref name="dir"/> to the specified <paramref name="currentFocusRect"/> and
/// which is able to get the focus.
/// This method will search the control tree down starting with this element as root element.
/// This method is only able to find focusable elements which are located at least one element outside the visible
/// range (see <see cref="AddPotentialFocusableElements"/>).
/// </summary>
/// <param name="currentFocusRect">The borders of the currently focused control.</param>
/// <param name="dir">Direction, the result control should be positioned relative to the
/// currently focused control.</param>
/// <returns>Framework element which should get the focus, or <c>null</c>, if this control
/// tree doesn't contain an appropriate control. The returned control will be
/// visible, focusable and enabled.</returns>
public virtual FrameworkElement PredictFocus(RectangleF? currentFocusRect, MoveFocusDirection dir)
{
if (!IsVisible || !IsEnabled)
return null;
ICollection<FrameworkElement> focusableChildren = new List<FrameworkElement>();
AddPotentialFocusableElements(currentFocusRect, focusableChildren);
// Check child controls
if (focusableChildren.Count == 0)
return null;
if (!currentFocusRect.HasValue)
return focusableChildren.First();
FrameworkElement result = FindNextFocusElement(focusableChildren, currentFocusRect, dir);
if (result != null)
return result;
return null;
}
protected bool AlignedPanelMoveFocus1(MoveFocusDirection direction)
{
FrameworkElement currentElement = GetFocusedElementOrChild();
if (currentElement == null)
return false;
RectangleF currentFocusRect = currentElement.ActualBounds;
ICollection<FrameworkElement> focusableChildren = new List<FrameworkElement>();
AlignedPanelAddPotentialFocusNeighbors(currentFocusRect, focusableChildren, true);
// Check child controls
if (focusableChildren.Count == 0)
return false;
FrameworkElement nextElement = FindNextFocusElement(focusableChildren, currentFocusRect, direction);
return nextElement != null && nextElement.TrySetFocus(true);
}
/// <summary>
/// Puts focus to some other block.
/// </summary>
/// <returns>true if successful, false if the method had no effect</returns>
/// <remarks>Normally called before deleting a block.</remarks>
public bool RemoveFocus(MoveFocusDirection direction)
{
Block neighbour = null;
if (direction == MoveFocusDirection.SelectPrev
|| direction == MoveFocusDirection.SelectPrevInChain)
{
if (direction == MoveFocusDirection.SelectPrev)
{
neighbour = this.FindPrevFocusableBlock();
}
else
{
neighbour = this.FindPrevFocusableBlockInChain();
}
if (neighbour == null)
{
// if there is no prev block,
// try to select next block
neighbour = this.FindNextFocusableBlock();
}
}
else if (direction == MoveFocusDirection.SelectNext
|| direction == MoveFocusDirection.SelectNextInChain)
{
if (direction == MoveFocusDirection.SelectNext)
{
neighbour = this.FindNextFocusableBlock();
}
else
{
neighbour = this.FindNextFocusableBlockInChain();
}
if (neighbour == null)
{
// if there is no next block,
// try to select previous block
neighbour = this.FindPrevFocusableBlock();
}
}
if (neighbour == null)
{
// if toRemoveFocusFrom is the only block,
// try to select parent
neighbour = this.FindNearestFocusableParent();
}
if (neighbour != null)
{
// if found someone, select it
neighbour.SetFocus();
}
return neighbour != null;
}
