[MFC]Message Map Macros

Begins the definition of your message map.

BEGIN_MESSAGE_MAP( theClass, baseClass )  

Parameters:

theClass

Specifies the name of the class whose message map this is.

baseClass

Specifies the name of the base class of theClass.

EX:

BEGIN_MESSAGE_MAP(CSystem_disk_power_cycle_STM32, CDialog)

ON_WM_PAINT()

ON_WM_QUERYDRAGICON()

ON_MESSAGE(WM_DEVICECHANGE, OnDeviceChange)

ON_WM_SYSCOMMAND()

ON_WM_TIMER()

ON_BN_CLICKED(IDC_BTN_SAVE, OnBtnSave)

// ON_MESSAGE(WM_GO_SYSTEM, OnUpdateMSG)

END_MESSAGE_MAP()

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Header: afxmsg_.h

ON_MESSAGE

Indicates which function will handle a user-defined message.

Syntax

Copy

ON_MESSAGE( message, memberFxn ) 

ex:

#define WM_MYMESSAGE (WM_USER + 100)

BEGIN_MESSAGE_MAP(CMyWnd2, CWnd)

   ON_MESSAGE(WM_MYMESSAGE, OnMyMessage)

END_MESSAGE_MAP()

// inside the class declaration

 afx_msg LRESULT OnMyMessage(WPARAM wParam, LPARAM lParam);

 LRESULT CMyWnd2::OnMyMessage(WPARAM wParam, LPARAM lParam)

{

   UNREFERENCED_PARAMETER(wParam);

   UNREFERENCED_PARAMETER(lParam);

   // Handle message here. 

   return 0;

}

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WM_APP

Used to define private messages, usually of the form WM_APP+x, where x is an integer value.

#define WM_APP                          0x8000

Range Meaning

0 through WM_USER –1

Messages reserved for use by the system.

WM_USER through 0x7FFF  (0x0400) to (0x7FFF )

Integer messages for use by private window classes.

WM_APP through 0xBFFF (0x8000) to (0xBFFF)

Messages available for use by applications.

0xC000 through 0xFFFF

String messages for use by applications.

Greater than 0xFFFF

Reserved by the system.

https://msdn.microsoft.com/library/windows/desktop/ms644930

https://docs.microsoft.com/en-us/cpp/mfc/reference/message-map-macros-mfc