This message expands or collapses the list of child items, if any, associated with the specified parent item. You can send this message explicitly or by using the TreeView_Expand macro.
At a Glance
| Header file: | Commctrl.h |
| Windows CE versions: | 1.0 and later (updated in 2.0) |
| Related macro: | TreeView_Expand |
Syntax
Parameters
flag
Action flag. It is one or more of the following values:
| Value | Description |
| TVE_COLLAPSE | Collapses the list. |
| TVE_COLLAPSERESET | Collapses the list and removes the child items. This flag must be used with the TVE_COLLAPSE flag. |
| TVE_EXPAND | Expands the list. |
| TVE_EXPANDPARTIAL | Version 4.70. Partially expands the list. In this state, the child items are visible and the parent item's plus symbol is displayed. This flag must be used in combination with the TVE_EXPAND flag. |
| TVE_TOGGLE | Collapses the list if it is expanded or expands it if it is collapsed. |
hItem
Handle to the parent item to expand or collapse.
Return Values
Nonzero indicates that a change took place. Zero indicates otherwise.
Remarks
In Windows CE versions 2.0 and later, you can use the new TVE_EXPANDPARTIAL flag in the flag parameter.
When the TVE_EXPANDPARTIAL flag is set, the child items are visible and parent item's plus symbol is displayed. This flag must be used in combination with the TVE_EXPAND flag.
The TVM_EXPAND message will cause the TVN_ITEMEXPANDING and TVN_ITEMEXPANDED notification messages to be generated if the item being expanded does not have the TVIS_EXPANDEDONCE state bit set. This state gets set when a parent item is expanded for the first time. Using TVE_COLLAPSE and TVE_COLLAPSERESET with TVM_EXPAND will cause the TVIS_EXPANDEDONCE state to be reset.
See Also