protected virtual void ApplyCollectionItemRemove(ApplyingCollectionChangeBundle bundle)
{
var contentContentChange = bundle.ContentContentChange;
var oldItems = contentContentChange.OldItems;
if (oldItems is null)
{
throw new ArgumentException("No old content-content-items were given although a remove collection change action has been triggered.");
}
var oldItemsCount = oldItems.Count;
var oldIndex = contentContentChange.OldIndex;
for (var oldItemIndex = oldItemsCount - 1; oldItemIndex >= 0; oldItemIndex--)
{
var removeIndex = oldItemIndex + oldIndex;
#if DEBUG
var removingContent = ContentList[removeIndex];
var oldContent = oldItems[oldItemIndex];
if (!EqualityComparer.Equals(removingContent, oldContent))
{
throw new Exception("Removing item is not equals old item that should be removed instead");
}
#endif
ItemList.RemoveAt(removeIndex);
ContentList.RemoveAt(removeIndex);
}
}
protected virtual void ApplyCollectionChangeBundle(ApplyingCollectionChangeBundle bundle)
{
switch (bundle.ContentContentChange.Action)
{
case NotifyCollectionChangedAction.Remove:
ApplyCollectionItemRemove(bundle);
break;
case NotifyCollectionChangedAction.Add:
ApplyCollectionItemAdd(bundle);
break;
case NotifyCollectionChangedAction.Move:
ApplyCollectionItemMove(bundle);
break;
case NotifyCollectionChangedAction.Replace:
ApplyCollectionItemReplace(bundle);
break;
case NotifyCollectionChangedAction.Reset:
ApplyCollectionReset(bundle);
break;
}
}
protected virtual void ApplyCollectionReset(ApplyingCollectionChangeBundle bundle)
{
var change = bundle.ItemContentChange;
var newContentList = change.NewItems ?? throw new ArgumentNullException(nameof(change.NewItems));
var newItemList = newContentList.Select(x => CreateItem(x));
void resetList <T>(IList <T> list, IEnumerable <T> newList)
{
list.Clear();
if (list is List <T> typedList)
{
typedList.AddRange(newList);
}
else
{
foreach (var item in newList)
{
list.Add(item);
}
}
}
resetList(ItemList, newItemList);
resetList(ContentList, newContentList);
}
private void applyCollectionChange(ICollectionChange <ContentType, ContentType> contentContentChange, out ICollectionChangeBundle <ItemType, ContentType> appliedBundle)
{
var itemContentChange = CreateItemContentCollectionChange(contentContentChange);
var applyingBundle = new ApplyingCollectionChangeBundle(itemContentChange, contentContentChange);
ApplyCollectionChangeBundle(applyingBundle);
appliedBundle = GetAppliedCollectionChangeBundle(applyingBundle);
}
protected AppliedCollectionChangeBundle GetAppliedCollectionChangeBundle(ApplyingCollectionChangeBundle applyingBundle)
{
var itemContentChange = applyingBundle.ItemContentChange;
var newItemList = itemContentChange.GetNewItems(ItemList);
var itemItemChange = itemContentChange.CreateOf(itemContentChange.OldItems, newItemList);
var appliedBundle = new AppliedCollectionChangeBundle(itemItemChange, applyingBundle.ItemContentChange, applyingBundle.ContentContentChange);
return(appliedBundle);
}
/// <summary>
/// Does regards <see cref="ObservableCollection{T}.Move(int, int)"/>, otherwise
/// it fallbacks to <see cref="IListGenericExtensions.Move{T}(IList{T}, int, int)"/>
/// </summary>
/// <param name="change"></param>
protected virtual void ApplyCollectionItemMove(ApplyingCollectionChangeBundle bundle)
{
var change = bundle.ItemContentChange;
void moveItem <T>(IList <T> list)
{
if (list is ObservableCollection <ItemType> observableList)
{
observableList.Move(change.OldIndex, change.NewIndex);
}
else
{
list.Move(change.OldIndex, change.NewIndex);
}
}
moveItem(ItemList);
moveItem(ContentList);
}
protected virtual void ApplyCollectionItemAdd(ApplyingCollectionChangeBundle bundle)
{
var itemContentChange = bundle.ItemContentChange;
var newContentContentItems = itemContentChange.NewItems;
if (newContentContentItems is null)
{
throw new ArgumentException("No new item-content-items were given although an add collection change action has been triggered.");
}
var newItemsCount = newContentContentItems.Count;
for (int itemIndex = 0; itemIndex < newItemsCount; itemIndex++)
{
var content = newContentContentItems[itemIndex];
var itemInsertIndex = itemContentChange.NewIndex + itemIndex;
var item = CreateItem(content);
ItemList.Insert(itemInsertIndex, item);
ContentList.Insert(itemInsertIndex, content);
}
}
/// <summary>
/// This method has no code inside and is ready for override.
/// </summary>
protected virtual void ApplyCollectionItemReplace(ApplyingCollectionChangeBundle bundle)
{
}
