Placing an icon in the system tray from an ATL COM server - with minimum hassle

// Shell Icon Helper - by Jon Taylor, for Code Project
// See documentation on Code Project web site for information on how 
// to use this class.

#ifndef __SHELLICONHELPER_H
#define __SHELLICONHELPER_H

#include <string>
#include <atlwin.h>

template <typename T>
class CShellIconHelper : public CWindowImpl<T>
{
private:

    virtual HRESULT CreateShell ()
    {
        RECT rect;
        rect.left = rect.right = rect.top = rect.bottom = 0;

        // Create a hidden window (using CWindowImpl)
        HWND hWnd = Create (NULL, rect, "ShellIconHiddenWindow", WS_POPUP);

        if (hWnd != 0) // Was created?
        {
            // Add the icon into the shell
            ShellNotify (NIM_ADD);
            return S_OK;
        }
        else return HRESULT_FROM_WIN32 (GetLastError());
    }
      
    virtual void DestroyShell ()
    {
        ShellNotify (NIM_DELETE); // Remove the icon
        if (m_hWnd != NULL)
        {
            // Get rid of the hidden window
            DestroyWindow();
        }
    }

    void ShellNotify (DWORD msg)
    {
        m_CurrentText = m_CurrentText;
        m_CurrentIconResource = m_CurrentIconResource;
        
        NOTIFYICONDATA notifyIconData;
        notifyIconData.cbSize = sizeof(notifyIconData);
        notifyIconData.hWnd = m_hWnd;
        notifyIconData.uFlags = NIF_ICON | NIF_MESSAGE | NIF_TIP;
        notifyIconData.uCallbackMessage = WM_USER;
        notifyIconData.uID = 0; 
           
        notifyIconData.hIcon = ::LoadIcon(_Module.GetResourceInstance(), MAKEINTRESOURCE (m_CurrentIconResource));
        ::lstrcpyn(notifyIconData.szTip, m_CurrentText.c_str(), 64); // Limit to 64 chars
        ::Shell_NotifyIcon (msg, &notifyIconData);    
    }
public:

    CShellIconHelper () 
    {
        // Initialise internal variables to known good state
        m_bVisible = false;
        m_bTimerActive = false;
        m_TimerId = 0;
        m_wTimerDuration = 0;
        m_CurrentIconResource = 0;
        m_CurrentText = std::string("");
    }
    
    virtual void SetShellTipText (std::string &TipText)
    {
        // Save this text for when we update
        m_CurrentText = TipText;
        ShellNotify (NIM_MODIFY);
    }

    virtual void SetShellIcon (WORD IconResource)
    {
        // Save this icon resource for when we update
        m_CurrentIconResource = IconResource;
        ShellNotify (NIM_MODIFY);
    }

    virtual void SetShellTimer (bool bEnabled, WORD wTimerDuration = 1000)
    {
        if (bEnabled == true) // User wants to start a timer
        {
            if (m_bTimerActive = true)
            {
                ::KillTimer (m_hWnd, m_TimerId);
            }
            // Start the timer
            m_TimerId = ::SetTimer (m_hWnd, 1, wTimerDuration, NULL);
        }
        else // User wants to shut down the timer
        {
            if (m_bTimerActive = true)
            {
                ::KillTimer (m_hWnd, m_TimerId);
            }
        }
        m_wTimerDuration = wTimerDuration;
        m_bTimerActive = bEnabled;
    }

    virtual void SetShellVisible (bool bVisible = true)
    {
        if (bVisible == true) // User wants to show the icon in the shell
        {
            if (m_bVisible == false) // Doesn't already exist?
            {
                // Create the shell, and timer (if applicable)
                CreateShell ();
            } // Otherwise, well you already have icon in the shell. :-)

            SetShellTimer (m_bTimerActive, m_wTimerDuration);

        }
        else // User wants rid of the icon
        { 
            if (m_bVisible == true)  // Is it there already?
            {
                // Destroy any running timer
                if (m_bTimerActive == true)
                {
                    ::KillTimer (m_hWnd, m_TimerId);
                }
                DestroyShell (); // Get rid
            }
        }

        m_bVisible = bVisible;
    }

    virtual WORD ShowPopupMenu (WORD PopupMenuResource)
    {
        HMENU hMenu, hPopup = 0;

        hMenu = ::LoadMenu (_Module.GetModuleInstance(), MAKEINTRESOURCE (PopupMenuResource));

        if (hMenu != 0)
        {
            POINT pt;
            ::GetCursorPos (&pt);

            // TrackPopupMenu cannot display the menu bar so get 
            // a handle to the first shortcut menu. 
            hPopup = ::GetSubMenu (hMenu, 0);

            // To display a context menu for a notification icon, the 
            // current window must be the foreground window before the 
            // application calls TrackPopupMenu or TrackPopupMenuEx. Otherwise, 
            // the menu will not disappear when the user clicks outside of the menu 
            // or the window that created the menu (if it is visible). 
            ::SetForegroundWindow (m_hWnd);

            WORD cmd = ::TrackPopupMenu (hPopup, TPM_RIGHTBUTTON | TPM_RETURNCMD, pt.x, pt.y, 0, m_hWnd, NULL);
            
            // See MS KB article Q135788
            ::PostMessage (m_hWnd, WM_NULL, 0, 0);

            // Clear up the menu, we're not longer using it.
            ::DestroyMenu (hMenu);
            return cmd;     
        }
		return 0;
    }



private:

    bool m_bVisible;
    bool m_bTimerActive;
    UINT_PTR m_TimerId;
    WORD    m_wTimerDuration;

    int m_CurrentIconResource;
    std::string m_CurrentText;
};

#endif