public ObjectPropertyAtom(IObjectInstance objectInstance, ClassProperty classProperty, bool hasChildObject)
: base(objectInstance, classProperty)
{
_hasChildObject = hasChildObject;
if (ClassProperty.CanRead)
{
// When the property is out of date, update it from the wrapped object.
_depProperty = new Computed(delegate
{
object value = ClassProperty.GetObjectValue(ObjectInstance.WrappedObject);
if (_hasChildObject)
{
IObjectInstance oldChild = _child;
object oldValue = oldChild == null ? null : oldChild.WrappedObject;
_child = null;
IObjectInstance wrapper;
if (value == null)
{
wrapper = null;
}
else if (value == oldValue)
{
wrapper = oldChild;
_child = wrapper;
}
else
{
if (WrapObject(value, out wrapper))
{
_child = wrapper;
}
}
ClassProperty.SetUserOutput(ObjectInstance, wrapper);
if (oldChild != _child && oldChild != null)
{
ObjectInstance.Tree.RemoveKey(oldValue);
oldChild.Dispose();
}
}
else
{
ClassProperty.SetUserOutput(ObjectInstance, value);
}
});
}
}
private void OnUpdateCollection()
{
IEnumerable values = ClassProperty.GetObjectValue(ObjectInstance.WrappedObject) as IEnumerable;
List <object> newCollection;
if (_hasChildObjects)
{
List <IObjectInstance> oldChildren = new List <IObjectInstance>(_children);
Dictionary <object, IObjectInstance> oldValues = oldChildren.ToDictionary(wrapper => wrapper.WrappedObject);
// Get the source collection from the wrapped object.
_children.Clear();
newCollection = new List <object>();
foreach (object value in values)
{
IObjectInstance wrapper;
if (oldValues.TryGetValue(value, out wrapper))
{
_children.Add(wrapper);
newCollection.Add(wrapper);
}
else
{
if (WrapObject(value, out wrapper))
{
_children.Add(wrapper);
}
newCollection.Add(wrapper);
}
}
foreach (IObjectInstance child in oldChildren.Except(_children))
{
ObjectInstance.Tree.RemoveKey(child.WrappedObject);
child.Dispose();
}
}
else
{
newCollection = values.OfType <object>().ToList();
}
AssignToObservableCollection(newCollection);
}
private void OnUpdateCollection()
{
// Get the source collection from the wrapped object.
IEnumerable source = ClassProperty.GetObjectValue(ObjectInstance.WrappedObject) as IEnumerable;
List <object> sourceCollection = source.OfType <object>().ToList();
// Delay the update to the observable collection so that we don't record dependencies on
// properties used in the items template. XAML will invoke the item template synchronously
// as we add items to the observable collection, thus causing other view model property
// getters to fire.
_delay = delegate
{
// Create a list of new items.
List <CollectionItem> items = new List <CollectionItem>();
// Dump all previous items into a recycle bin.
using (RecycleBin <CollectionItem> bin = new RecycleBin <CollectionItem>())
{
foreach (object oldItem in _collection)
{
bin.AddObject(new CollectionItem(_collection, oldItem, true));
}
// Add new objects to the list.
if (sourceCollection != null)
{
foreach (object obj in sourceCollection)
{
items.Add(bin.Extract(new CollectionItem(_collection, TranslateOutgoingValue(obj), false)));
}
}
// All deleted items are removed from the collection at this point.
}
// Ensure that all items are added to the list.
int index = 0;
foreach (CollectionItem item in items)
{
item.EnsureInCollection(index);
++index;
}
};
}
public ObjectPropertyAtom(IObjectInstance objectInstance, ClassProperty classProperty)
: base(objectInstance, classProperty)
{
if (ClassProperty.CanRead)
{
// When the property is out of date, update it from the wrapped object.
_depProperty = new Computed(delegate
{
object value = ClassProperty.GetObjectValue(ObjectInstance.WrappedObject);
value = TranslateOutgoingValue(value);
if (!Object.Equals(_value, value))
{
_value = value;
}
if (_firePropertyChanged)
{
ObjectInstance.FirePropertyChanged(ClassProperty.Name);
}
_firePropertyChanged = true;
});
// When the property becomes out of date, trigger an update.
_depProperty.Invalidated += () => UpdateScheduler.ScheduleUpdate(UpdateNow);
}
}