private Request _getNewRequest(UIElement e)
{
Request r;
if (_pocket != null)
{
r = _pocket;
_pocket = r.Next;
_pocketSize--;
r.Next = r.Prev = null;
}
else
{
ContextLayoutManager lm = ContextLayoutManager.From(e.Dispatcher);
try
{
r = new Request();
}
catch (System.OutOfMemoryException ex)
{
if (lm != null)
{
lm.setForceLayout(e);
}
throw ex;
}
}
r.Target = e;
return(r);
}
private static object UpdateLayoutCallback(object arg)
{
ContextLayoutManager ContextLayoutManager = arg as ContextLayoutManager;
if (ContextLayoutManager != null)
{
ContextLayoutManager.UpdateLayout();
}
return(null);
}
/// <summary>
/// The way to obtain ContextLayoutManager associated with particular Dispatcher.
/// </summary>
/// <param name="dispatcher">A dispatcher for which ContextLayoutManager is queried.
/// There is only one ContextLayoutManager associuated with all elements in a single context</param>
/// <returns>ContextLayoutManager</returns>
internal static ContextLayoutManager From(Dispatcher dispatcher)
{
ContextLayoutManager lm = dispatcher.Reserved3 as ContextLayoutManager;
if(lm == null)
{
if(Dispatcher.CurrentDispatcher != dispatcher)
{
throw new InvalidOperationException();
}
lm = new ContextLayoutManager();
dispatcher.Reserved3 = lm;
}
return lm;
}
/// <summary>
/// The way to obtain ContextLayoutManager associated with particular Dispatcher.
/// </summary>
/// <param name="dispatcher">A dispatcher for which ContextLayoutManager is queried.
/// There is only one ContextLayoutManager associuated with all elements in a single context</param>
/// <returns>ContextLayoutManager</returns>
internal static ContextLayoutManager From(Dispatcher dispatcher)
{
ContextLayoutManager lm = dispatcher.Reserved3 as ContextLayoutManager;
if (lm == null)
{
if (Dispatcher.CurrentDispatcher != dispatcher)
{
throw new InvalidOperationException();
}
lm = new ContextLayoutManager();
dispatcher.Reserved3 = lm;
}
return(lm);
}
internal void Add(UIElement e)
{
if (getRequest(e) != null)
{
return;
}
if (e.CheckFlagsAnd(VisualFlags.IsLayoutSuspended))
{
return;
}
RemoveOrphans(e);
UIElement parent = e.GetUIParentWithinLayoutIsland();
if (parent != null && canRelyOnParentRecalc(parent))
{
return;
}
ContextLayoutManager layoutManager = ContextLayoutManager.From(e.Dispatcher);
if (layoutManager._isDead)
{
return;
}
//10 is arbitrary number here, simply indicates the queue is
//about to be filled. If not queue is not almost full, simply add
//the element to it. If it is almost full, start conserve entries
//by escalating invalidation to all the ancestors until the top of
//the visual tree, and only add root of visula tree to the queue.
if (_pocketSize > PocketReserve)
{
_addRequest(e);
}
else
{
//walk up until we are the topmost UIElement in the tree.
//on each step, mark the parent dirty and remove it from the queues
//only leave a single node in the queue - the root of visual tree
while (e != null)
{
UIElement p = e.GetUIParentWithinLayoutIsland();
invalidate(e); //invalidate in any case
if (p != null && p.Visibility != Visibility.Collapsed) //not yet a root or a collapsed node
{
Remove(e);
}
else //root of visual tree or a collapsed node
{
if (getRequest(e) == null)
{
RemoveOrphans(e);
_addRequest(e);
}
}
e = p;
}
}
layoutManager.NeedsRecalc();
}
