The TVM_EXPAND 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.
TVM_EXPAND
wParam = (WPARAM) (UINT) flag;
lParam = (LPARAM) (HTREEITEM) hitem;
Parameters
flag
Action flag. This parameter can be one of the following values:
| Value | Meaning |
| TVE_COLLAPSE | Collapses the list. |
| TVE_COLLAPSERESET | Collapses the list and removes the child items. Note that TVE_COLLAPSE must also be specified. |
| TVE_EXPAND | Expands the list. |
| TVE_TOGGLE | Collapses the list if it is currently expanded or expands it if it is currently collapsed. |
hitem
Handle to the parent item to expand or collapse.
Return Values
Returns TRUE if any change took place or FALSE otherwise.
Remarks
This message does not send the TVN_ITEMEXPANDING and TVN_ITEMEXPANDED notification messages to the parent window.
See Also