| Parameter | Description |
|---|---|
| item | Item to add. |
| parentId | The parent id for the item. |
| childIndex | The child index in the parent's children list. |
| rebuildTree | Whether to refresh the tree data immediately. If <c>false</c>, call <see cref="BaseVerticalCollectionView.RefreshItems()" />. |
Adds an item to the tree.