Button Notification Messages
Windows Predefined Controls – Part 10
Volume - Windows User Interface
Forward: In this part of the series, we look at Button Notification Messages.
By: Chrysanthus Date Published: 29 Aug 2012
Introduction
Note: If you cannot see the code or if you think anything is missing (broken link, image absent), just contact me at forchatrans@yahoo.com. That is, contact me for the slightest problem you have about what you are reading.
Notification
When a user acts (uses) on a control, that is an event. A message of the event is sent to the window procedure of the parent window. Such a message is called a notification. I explained the details of notifications in a tutorial of this series, titled, “Control Messages”. I now give you a list of Button notifications and their meanings.
Notification Code: Meaning
BN_CLICKED: This message is sent when the user clicks a button. The parent window of the button receives the BN_CLICKED notification code in the form of a WM_COMMAND message.
BN_DBLCLK: This notification code is sent when the user double-clicks a button. This notification code is sent automatically for BS_USERBUTTON, BS_RADIOBUTTON, and BS_OWNERDRAW buttons. Other button types send BN_DBLCLK only if they have the BS_NOTIFY style. The parent window of the button receives the BN_DBLCLK notification code in the form of a WM_COMMAND message.
BN_DOUBLECLICKED: This notification is sent when the user double-clicks a button. This notification is sent automatically for BS_USERBUTTON, BS_RADIOBUTTON, and BS_OWNERDRAW buttons. Other button types send BN_DOUBLECLICKED only if they have the BS_NOTIFY style. The parent window of the button receives the BN_DOUBLECLICKED notification code in the form of a WM_COMMAND message. BN_DOUBLECLICKED is the same as BN_DBLCLK.
BN_KILLFOCUS: This notification is sent when a button loses the keyboard focus. The button must have the BS_NOTIFY style to send this notification code. The parent window of the button receives the BN_KILLFOCUS notification code in the form of a WM_COMMAND message.
BN_SETFOCUS: This notification is sent when a button receives the keyboard focus. The button must have the BS_NOTIFY style to send this notification code. The parent window of the button receives the BN_SETFOCUS notification code in the form of a WM_COMMAND message.
BCN_DROPDOWN: This code is 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.
That is it for this part of the series. We stop here and continue in the next part.
Chrys
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