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TBN_DROPDOWN notification code

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Sent by a toolbar control when the user clicks a dropdown button. This notification code is sent in the form of a WM_NOTIFY message.

TBN_DROPDOWN

    lpnmtb = (LPNMTOOLBAR) lParam;

Parameters

lParam

Pointer to an NMTOOLBAR structure that contains information about this notification code. For this notification code, only the hdr and iItem members of this structure are valid.

Return value

Returns one of the following values:

Return code Description
TBDDRET_DEFAULT
 The drop-down was handled.
TBDDRET_NODEFAULT
 The drop-down was not handled.
TBDDRET_TREATPRESSED
 The drop-down was handled, but treat the button like a regular button.

Remarks

Note

Dropdown buttons can be plain (BTNS_DROPDOWN style), display an arrow next to the button image (BTNS_WHOLEDROPDOWN style), or display an arrow that is separated from the image (TBSTYLE_EX_DRAWDDARROWS style). If a separated arrow is used, TBN_DROPDOWN is sent only if the user clicks the arrow portion of the button. If the user clicks the main part of the button, a WM_COMMAND message with button's ID is sent, just as with a standard button. For the other two styles of dropdown button, TBN_DROPDOWN is sent when the user clicks any part of the button.

Requirements

Requirement Value
Minimum supported client
 Windows Vista [desktop apps only]
Minimum supported server
 Windows Server 2003 [desktop apps only]
Header
Commctrl.h