public void UpdateFilter(IPredicate<object> predicate)
{
if ((_predicate == null) && (predicate == null)) {
return;
}
UpdateVersion();
if (_snapShot == null) {
RaisePropertyChanged("Count");
RaiseCollectionReset();
}
else {
object currentItem = null;
if (IsCurrencyEnabled) {
currentItem = CurrentItem;
}
// Potentially some items in the view are no longer in the snapshot and some new items
// now become part of the snapshot. First we'll remove any that no longer should be in
// the snapshot, and then we'll add whatever is.
if (predicate != null) {
for (int i = _snapShot.Count - 1; i >= 0; i--) {
object item = _snapShot[i];
if (predicate.Filter(item) == false) {
RemoveItem(item, i, /* raisePropertyChange */ false);
}
}
}
if (_predicate != null) {
foreach (object item in _sourceData) {
if ((_predicate.Filter(item) == false) &&
((predicate == null) || predicate.Filter(item))) {
AddItem(item, /* raisePropertyChange */ false);
}
}
}
if (currentItem != null) {
bool currentItemChanged = false;
int index = _snapShot.IndexOf(currentItem);
if (index == -1) {
index = 0;
}
CurrentIndex = index;
RaisePropertyChanged("CanMovePrevious");
RaisePropertyChanged("CanMoveNext");
if (currentItemChanged) {
RaisePropertyChanged("CurrentItem");
}
}
}
_predicate = predicate;
RaisePropertyChanged("Count");
}