/// <summary>
/// Attaches event listeners to elements that possess them.
/// </summary>
void Attach()
{
var evt = attributes.Event;
if (evt == null)
{
return;
}
if (handler.Value == null)
{
throw new DOMTargetEventException(Element, Events.Error);
}
if (observer.Value == null)
{
throw new DOMTargetEventException(Element, Events.Error);
}
observer.Value.Register(
evt,
InterfaceEventListener.Create(InvokeHandleEvent),
GetCapture());
}
/// <summary>
/// Dynamically generate repeat items, reusing existing instances if available.
/// </summary>
/// <returns></returns>
public void Update()
{
// refresh binding
if (Binding != null)
{
Binding.Recalculate();
}
// configure listener for instance alterations
if (Binding != null &&
Binding.Context != null)
{
if (listener == null)
{
var target = Binding.Context.Instance.Element.Parent.Interface <EventTarget>();
// find existing listener
listener =
InterfaceEventListener.GetListener(target, Events.Insert, true, Update) ??
InterfaceEventListener.GetListener(target, Events.Delete, true, Update);
// register listener
if (listener == null)
{
listener = InterfaceEventListener.Create(Update);
target.Register(Events.Insert, listener, true);
target.Register(Events.Delete, listener, true);
}
}
}
// store current index item
var indexPrev = Index;
var indexItem = Element
.Elements()
.FirstOrDefault(i => i.AnnotationOrCreate <RepeatItemState>().Index == Index);
// build new list of properly ordered nodes
var items = Binding != null?Binding.ModelItems.Select(i => i.Xml).ToArray() : new XObject[0];
var nodes = Element.Elements().ToArray();
var sorts = new XElement[items.Length];
for (int index = 0; index < items.Length; index++)
{
// model item at current index
var item = items[index];
// get existing item or create new
var indx = Array.FindIndex(nodes, i => i.AnnotationOrCreate <RepeatItemState>().ModelObjectId == item.GetObjectId());
var node = indx >= 0 ? nodes[indx] : null;
if (node == null)
{
node = new XElement(
Constants.XForms_1_0 + "group",
Template.GetNamespacePrefixAttributes(),
Template.Nodes());
}
// set node into output list
sorts[index] = node;
// configure item state
var anno = node.AnnotationOrCreate <RepeatItemState>();
anno.ModelObjectId = item.GetObjectId();
anno.Index = index + 1;
anno.Size = items.Length;
}
// new sequence is different from old sequence
if (sorts.Length != nodes.Length ||
sorts.SequenceEqual(nodes) == false)
{
// replace all children
Element.RemoveNodes();
Element.Add(sorts);
// set of elements that were added
var added = sorts
.Except(nodes)
.ToArray();
// model-construct-done sequence applied to new children
foreach (var node in added)
{
foreach (var i in GetAllExtensions <IOnRefresh>(node))
{
i.RefreshBinding();
}
}
// discard refresh events
foreach (var node in added)
{
foreach (var i in GetAllExtensions <IOnRefresh>(node))
{
i.DiscardEvents();
}
}
// final refresh
foreach (var node in added)
{
foreach (var i in GetAllExtensions <IOnRefresh>(node))
{
i.Refresh();
}
}
}
// restore or reset index
var length = Element.Elements().Count();
if (indexItem != null &&
indexItem.Parent != null)
{
Index = indexItem.AnnotationOrCreate <RepeatItemState>().Index;
}
else if (indexPrev > 0)
{
Index = indexPrev <= length ? indexPrev : length;
}
else if (length > 0)
{
Index = 1;
}
else
{
Index = 0;
}
}
