BCN_DROPDOWN notification code
Sent when the user clicks a drop down arrow on a button. The parent window of the control receives this notification code in the form of a WM_NOTIFY message.
A pointer to a NMBCDROPDOWN structure. The rcButton member is set to describe the drop-down area.
No return value.
The notification receiver casts LPARAM to retrieve the NMBCDROPDOWN structure. WPARAM contains the ID of the control that sends this message. The button control must have a drop-down button style.
Minimum supported client
|Windows Vista [desktop apps only]|
Minimum supported server
|Windows Server 2008 [desktop apps only]|
Build date: 11/16/2013