internal static bool IsItemContainedInAllSourceItems <TItemSource>(
IViewModel selectionVM,
TItemSource sourceItem
)
{
IEnumerable <TItemSource> allSourceItems = GetAllSourceItems <TItemSource>(selectionVM);
return(allSourceItems.Contains(sourceItem, ReferenceEqualityComparer <TItemSource> .CreateSmartComparer()));
}
public WrapperCollectionAccessorBehavior(
bool shouldCacheSourceCollection,
IEqualityComparer <TItemSource> reusabilitySourceComparer = null
)
{
_shouldCacheSourceCollection = shouldCacheSourceCollection;
_reusabilitySourceComparer =
reusabilitySourceComparer ??
ReferenceEqualityComparer <TItemSource> .CreateSmartComparer();
}
private Dictionary <TItemSource, TItemVM> GetCache(IBehaviorContext context)
{
Dictionary <TItemSource, TItemVM> cache;
if (!context.FieldValues.TryGetValue(_cache, out cache))
{
// Reference equality because:
// (1) If the source objects are reloaded in a new NHibernate session,
// the are equal to the old object and thus item VMs would be mistakenly
// reused.
// (2) If two items of the all source items collection are equal, only one
// view model would be created for both.
cache = new Dictionary <TItemSource, TItemVM>(ReferenceEqualityComparer <TItemSource> .CreateSmartComparer());
context.FieldValues.SetValue(_cache, cache);
}
return(cache);
}
