/// <summary>
/// Called when children have been added to an item.
/// </summary>
/// <param name="item">The item.</param>
/// <param name="startIndex">Index where the first child is added.</param>
/// <param name="itemList">The list of children.</param>
protected virtual void OnItemAddChildren(object item, int startIndex, IList itemList)
{
NotifyPreviewCollectionModified(TreeViewCollectionOperation.Insert);
if (IsExpanded(item))
{
int ShownPreviousChildrenCount = VisibleChildren.IndexOf(item);
ShownPreviousChildrenCount += CountPreviousChildrenExpanded(item, startIndex, -1);
int ShownIndex = ShownPreviousChildrenCount;
IInsertItemContext Context = CreateInsertItemContext(item, ShownIndex);
Context.Start();
#if NETCOREAPP3_1
foreach (object?ChildItem in itemList)
{
if (ChildItem != null)
{
InsertChildren(Context, ChildItem, item);
}
}
#else
foreach (object ChildItem in itemList)
{
InsertChildren(Context, ChildItem, item);
}
#endif
Context.Complete();
Context.Close();
}
NotifyCollectionModified(TreeViewCollectionOperation.Insert);
}
private void OnItemMoveChildrenPreviousAfter(object item, int oldIndex, int newIndex, IList itemList)
{
int ShownPreviousChildrenCount = VisibleChildren.IndexOf(item);
int RemoveIndex = ShownPreviousChildrenCount;
RemoveIndex += CountPreviousChildrenExpanded(item, oldIndex + 1, newIndex);
IRemoveItemContext RemoveContext = CreateRemoveItemContext(item, RemoveIndex);
RemoveContext.Start();
#if NETCOREAPP3_1
foreach (object?ChildItem in itemList)
{
if (ChildItem != null)
{
RemoveChildren(RemoveContext, ChildItem);
}
}
#else
foreach (object ChildItem in itemList)
{
RemoveChildren(RemoveContext, ChildItem);
}
#endif
RemoveContext.Complete();
RemoveContext.Close();
int InsertIndex = ShownPreviousChildrenCount;
InsertIndex += CountPreviousChildrenExpanded(item, newIndex, -1);
IInsertItemContext InsertContext = CreateInsertItemContext(item, InsertIndex);
InsertContext.Start();
#if NETCOREAPP3_1
foreach (object?ChildItem in itemList)
{
if (ChildItem != null)
{
InsertChildren(InsertContext, ChildItem, item);
}
}
#else
foreach (object ChildItem in itemList)
{
InsertChildren(InsertContext, ChildItem, item);
}
#endif
InsertContext.Complete();
InsertContext.Close();
}
/// <summary>
/// Inserts child items starting from the content root.
/// </summary>
protected override void InsertChildrenFromRootDontNotify()
{
if (Content is TItem Item)
{
IInsertItemContext Context = CreateInsertItemContext(Item, 0);
Context.Start();
InsertChildren(Context, Item, null);
Context.Complete();
Context.Close();
}
}