MFC messageloop in dialog window

Question

i created a MFC dialog application.

now i want to use a messageloop, but i can not find it. I read that mfc will create it for me but that it will be hidden. so how can i manipulate the messageloop?

i need the messageloop to recieve events from my tray icon which i created for that application.

so that i can use something like that:

long CALLBACK WndProc(HWND hWnd, UINT nMsg, UINT wParam, LONG lParam) 
{ 
   switch(nMsg) 
   { 
   case (WM_USER + 1): 
      { 
         switch(lParam) 
         { 
         case WM_RBUTTONUP: 
            { 
               /**/
            } 
         } 
         return 0; 
      } 

   default: 
      return DefWindowProc(hWnd, nMsg, wParam, lParam); 
   } 
}

I'm still a beginner at mfc.

Answer 1

After installing an icon to the system tray by Shell_NotifyIcon, this icon become the extension of your dialog UI. When the user interact with this icon, the UI messages will be re-directed to your dialog by the OS automatically.

To serve these user messages you needs to perform few steps:

(1) Add a message handler definition (ON_MESSAGE(WM_TRAY_NOTIFY, OnTrayNotify)) inside the (.cpp) file. Must be inside the BEGIN_MESSAGE_MAP/END_MESSAGE_MAP block:

BEGIN_MESSAGE_MAP(CTestDlg, CDialog)
   //{{AFX_MSG_MAP(CTestDlg)
   ON_WM_PAINT()
   ON_WM_QUERYDRAGICON()
   ...
   //}}AFX_MSG_MAP
   ON_MESSAGE(WM_TRAY_NOTIFY, OnTrayNotify)
END_MESSAGE_MAP()

(2) Add a message handler implementation in the (.cpp) file, to perform the actual work

void CTestDlg::OnTrayNotify(UINT nID, LPARAM lEvent)
{
    if (nID==TRAYICON_ID1)
    {   
        // handle messages here
        if (lEvent==WM_LBUTTONDBLCLK)
        {  // do left button double click, usually restore application
        }
        if (lEvent==WM_RBUTTONUP)
        {  // do right button up, usually popup a menu at clicked location
        }
    }
}

(3) Add a prototype definition of this message handler (afx_msg void OnTrayNotify(UINT nID, LPARAM lEvent);) inside the (.h) file. Must be inside the BEGIN_MESSAGE_MAP/END_MESSAGE_MAP block:

// Generated message map functions
//{{AFX_MSG(CTestDlg)
virtual BOOL OnInitDialog();
afx_msg void OnPaint();
afx_msg HCURSOR OnQueryDragIcon();
...
//}}AFX_MSG
afx_msg void OnTrayNotify(UINT nID, LPARAM lEvent);
DECLARE_MESSAGE_MAP()

(4) Add definition inside (.h) file

#define WM_TRAY_NOTIFY WM_USER+567
#define TRAYICON_ID1 0x1234

The code above is assuming:

• The dialog name is CTestDlg, change it to your dialog name
• The user-callback-message identifier (uCallbackMessage) used to setup Shell_NotifyIcon is WM_TRAY_NOTIFY
• The identifier of the tray icon (uID) sed to setup Shell_NotifyIcon is TRAYICON_ID1