| id | 层级视图项标识符。 |
| outChildren | 使用项的具有子项的所有子项标识符填充的列表。 |
用于获取具有其他子项的层级视图项后代的列表。
The result is written to outChildren list which is resized if necessary.
The call builds the whole hierarchy view tree and can be expensive.
另请参阅：TreeView.GetDescendantsThatHaveChildren。