public static void SetFocusToFocusScope(IInputElement newFocus)
{
UIElement newElementFocus = newFocus as UIElement;
if (newElementFocus != null)
{
UIElement focusScope = FocusManager.GetFocusScope(newElementFocus) as UIElement;
int priority = FocusScopeManager.GetFocusScopePriority(focusScope);
if (priority != FocusScopeManager.DefaultFocusScopePriority)
{
FocusScopeManager.Instance.OnScopeKeyboardFocusChanged(focusScope, priority);
}
}
}
private static void HandlePreviewGotKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
if (FocusScopeManager.Instance.ShouldDenyFocusChange)
{
e.Handled = true;
return;
}
DependencyObject newFocusObject = e.NewFocus as DependencyObject;
// if there is a newly focused object and it is not allowed focus
if (newFocusObject != null && !FocusScopeManager.GetAllowedFocus(newFocusObject))
{
// Push focus back to the client's desired focus sink and cancel the change
// of focus to new focus.
FocusScopeManager.Instance.ReturnFocus();
e.Handled = true;
}
}
private bool IsFocusScopeManaged(UIElement focusScope, int priority, int priorityStartIndex)
{
for (int curScopeIndex = priorityStartIndex; curScopeIndex < this.scopes.Count; curScopeIndex++)
{
WeakReference curRef = this.scopes[curScopeIndex];
if (curRef.IsAlive)
{
UIElement curTarget = (UIElement)curRef.Target;
if (FocusScopeManager.GetFocusScopePriority(curTarget) > priority)
{
return(false);
}
if (curTarget == focusScope)
{
return(true);
}
}
}
return(false);
}
private object CoerceFocusedElement(object newFocus)
{
UIElement newFocusElement = newFocus as UIElement;
if (newFocusElement != null)
{
// If we have been told to deny the next focus change then do so
if (this.ShouldDenyFocusChange)
{
this.EndDenyNextFocusChange();
return(DependencyProperty.UnsetValue);
}
// Don't allow logical focus to go to elements that are not focusable.
if (newFocus != null && !FocusScopeManager.GetAllowedFocus(newFocusElement))
{
return(DependencyProperty.UnsetValue);
}
}
return(newFocus);
}
private int FindStartIndexForPriority(int priority)
{
int startIndex = 0;
for (; startIndex < this.scopes.Count; startIndex++)
{
WeakReference curRef = this.scopes[startIndex];
if (curRef.IsAlive)
{
if (FocusScopeManager.GetFocusScopePriority((UIElement)curRef.Target) >= priority)
{
break;
}
}
else
{
this.listContainsDeadReferences = true;
}
}
return(startIndex);
}
