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<FONT COLOR="#000099">TrayIcon</FONT></H3></CENTER>
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This code was contributed by <A HREF="mailto: Chris.Maunder@cbr.clw.csiro.au">Chris Maunder</A>.
<p>
<img src="trayicon.gif" width=157 height=31 border=0 alt="TrayIcon example image" align="bottom">
<A HREF="TrayIcon.zip">Download source files</A> (3Kb) or <A HREF="SystemTray.zip">Sample Project</a> (31.3Kb).
</p>
<p>
<A HREF="TrayIcon.html#Intro">Introduction</A><br>
<A HREF="TrayIcon.html#Construction">Construction</A><br>
<A HREF="TrayIcon.html#Operations">Operations</A><br>
<A HREF="TrayIcon.html#Default">Default message handling</A><br>
<A HREF="TrayIcon.html#Example">Example of use</A><br>
<A HREF="TrayIcon.html#TrackPopupMenu">NOTE on TrackPopupMenu</A><br>
</P>
<h4><A NAME="Intro">Introduction</a></h4>
<P>This is a conglomeration of ideas from the MSJ "Webster" application,
sniffing round the online docs, and from other implementations such
as PJ Naughter's "CTrayIconifyIcon" (<A HREF="http://indigo.ie/~pjn/ntray.html">
http://indigo.ie/~pjn/ntray.html</A>) especially the "CTrayIcon::OnTrayNotification"
member function and the SetStandardIcon stuff.
<P>This class is a light wrapper around the windows system tray stuff. It
adds an icon to the system tray with the specified ToolTip text and
callback notification value, which is sent back to the Parent window.
<P>The basic steps to using a tray icon via the windows API are:
<ol>
<li>Load up the <tt>NOTIFYICONDATA</tt> structure</li>
<li>Call <tt>Shell_NotifyIcon(NIM_ADD, &MyTrayNotifyStruct)</tt></li>
</ol>
<P>Changing the values of the fields in NOTIFYICONDATA and calling
Shell_NotifyIcon allows you to change to icon or tool tip text or remove
the icon itelf. All this messing around has been bundled in a class wrapper
to make it easier and neater.
<P>The tray icon can be instantiated using either the constructor or by
declaring the object and creating (and displaying) it later on in the
program. eg.
<PRE><TT><FONT COLOR="#990000"> CTrayIcon m_TrayIcon; // Member variable of some class
...
// in some member function maybe...
m_TrayIcon.Create(pParentWnd, WM_MY_NOTIFY, "Click here",
hIcon, nTrayIconID);
</FONT></TT></PRE>
<a name="Construction"><H4>Construction</H4></a>
<PRE><TT><FONT COLOR="#990000"> CTrayIcon();
CTrayIcon(CWnd* pWnd, UINT uCallbackMessage, LPCTSTR szToolTip, HICON icon, UINT uID);
BOOL Create(CWnd* pWnd, UINT uCallbackMessage, LPCTSTR szToolTip, HICON icon, UINT uID);
</FONT></TT></PRE>
<P>Note that the destructor automatically removes the icon from the tray.</P>
<FONT COLOR="#990000">
<TABLE CELLSPACING=0 BORDER=0 WIDTH="100%">
<TR><td WIDTH="10%"> </td>
<TD WIDTH="30%"><tt>pWnd</tt></TD>
<TD WIDTH="65%">Parent window where notification messages will be sent</TD>
</TR>
<TR>
<td WIDTH="5%"> </td>
<TD WIDTH="30%"><tt>uCallbackMessage</tt></TD>
<TD WIDTH="65%">The notification messages that will be sent to the parent window</TD>
</TR>
<TR>
<td WIDTH="5%"> </td>
<TD WIDTH="30%"><tt>szToolTip</tt></TD>
<TD WIDTH="65%">Tooltip for the tray icon</TD>
</TR>
<TR>
<td WIDTH="5%"> </td>
<TD WIDTH="30%"><tt>icon</tt></TD>
<TD WIDTH="65%">Handle to the icon to be displayed</TD>
</TR>
<TR>
<td WIDTH="5%"> </td>
<TD WIDTH="30%"><tt>uID</tt></TD>
<TD WIDTH="65%">Tray icon ID</TD>
</TR>
</TABLE>
</FONT>
<h4><A NAME="Operations">Operations</a></h4>
<PRE><TT><FONT COLOR="#990000"> LRESULT OnTrayNotification(WPARAM wID,
LPARAM lEvent) // Discussed below
void MoveToRight() // Moves the icon to the far right of the tray,
// so it is immediately to the left of the clock
void RemoveIcon() // Removes the icon from the tray (icon can no
// longer be manipulated)
void HideIcon() // Hides but does not totally remove the icon
// from the tray.
void ShowIcon() // Redisplays a previously hidden icon
BOOL SetTooltipText(LPCTSTR pszTip) // Set Tooltip text
BOOL SetTooltipText(UINT nID) // Set tooltip from text resource ID
CString GetTooltipText() const // Retrieve tool tip text
BOOL SetNotificationWnd(CWnd* pWnd) // Self explanatory
CWnd* GetNotificationWnd() const
HICON GetIcon() const // Get current tray icon
BOOL SetIcon(HICON hIcon) // Change tray icon. Returns FALSE if unsuccessful
BOOL SetIcon(LPCTSTR lpszIconName) // Same, using name of the icon resource
BOOL SetIcon(UINT nIDResource) // Same, using icon resource ID
BOOL SetStandardIcon(LPCTSTR lpIconName) // Load icon from the current application.
BOOL SetStandardIcon(UINT nIDResource)
</FONT></TT></PRE></p>
<p>SetStandardIcon can also take any of the following values:</p>
<p>
<PRE><TT> <u> </u>
<u>nIDResource Description </u>
IDI_APPLICATION Default application icon.
IDI_ASTERISK Asterisk (used in informative messages).
IDI_EXCLAMATION Exclamation point (used in warning messages).
IDI_HAND Hand-shaped icon (used in serious warning messages).
IDI_QUESTION Question mark (used in prompting messages).
<u>IDI_WINLOGO Windows logo </u>
</TT></PRE>
<h4><A NAME="Default">Default message handling</a></h4>
The parent window, on receiving a notification message, can redirect this
message back to the tray icon for handling be calling
<strong>CTrayIcon::OnTrayNotification(...)</strong>. The default implementation
tries to find a menu with the same resource ID as the tray icon. If it finds a
menu and the event received was a right mouse button up, then the submenu is
displayed as a context menu. If a double click was received, then the message
ID of first item in the submenu is sent back to the parent window.
<h4><A NAME="Example">Example of use</a></h4>
A good place to declare the tray icon is in your CFrameWnd derived class.<br>
eg.
<PRE><TT><FONT COLOR="#990000"> #define WM_ICON_NOTIFY WM_USER+10
CTrayIcon m_TrayIcon
</FONT></TT></PRE>
Add a message map entry for the tray icon notification:
<PRE><TT><FONT COLOR="#990000"> BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd)
...
ON_MESSAGE(WM_ICON_NOTIFY, <strong>OnTrayNotification</strong>)
END_MESSAGE_MAP()
</FONT></TT></PRE>
Create the icon (maybe in your OnCreate):
<PRE><TT><FONT COLOR="#990000"> if (!m_TrayIcon.Create(this, WM_ICON_NOTIFY, strToolTip, hIcon, IDR_POPUP_MENU))
return -1;
</FONT></TT></PRE>
where IDR_POPUP_MENU is the ID of a popup menu to display for the icon.
You then need a handler for the tray icon notification message:
<PRE><TT><FONT COLOR="#990000"> LRESULT CMainFrame::OnTrayNotification(WPARAM wParam, LPARAM lParam)
{
// Delegate all the work back to the default implementation in CTrayIcon.
return m_TrayIcon.OnTrayNotification(wParam, lParam);
}
</FONT></TT></PRE>
The menu used (IDR_POPUP_MENU) looks like the following:
<PRE><TT><FONT COLOR="#990000"> IDR_POPUP_MENU MENU PRELOAD DISCARDABLE
BEGIN
POPUP "POPUP_MENU"
BEGIN
MENUITEM "&About...", ID_APP_ABOUT
MENUITEM SEPARATOR
MENUITEM "&Options...", ID_APP_OPTIONS
MENUITEM SEPARATOR
MENUITEM "E&xit", ID_APP_EXIT
END
END
</FONT></TT></PRE>
A single right click on the tray icon will bring up this menu, while
a double click will send a ID_APP_ABOUT message back to the frame.
<h4><A NAME="TrackPopupMenu">NOTE on TrackPopupMenu</a></h4>
Many people have had troubles using TrackPopupMenu. They have reported that the popup
menu will often not disappear once the mouse is clicked outside of the menu, even though
they have set the last parameter of TrackPopupMenu() as NULL. This is a Microsoft
"feature", and is by design. The mind boggles, doesn't it?</p>
<p>Anyway - to workaround this "feature", one must set the current window as the
foreground window <em>before</em> calling TrackPopupMenu. This then causes a second
problem - namely that the next time the menu is displayed it displays then immediately
disappears. To fix <em>this</em> problem, you must make the currernt application
active after the menu disappears. This can be done by sending a benign message such
as WM_USER to the current window.</p>
<p>So - what should have been a simple:
<PRE><TT><FONT COLOR="#990000"> TrackPopupMenu(hSubMenu, TPM_RIGHTBUTTON, pt.x,pt.y, 0, hDlg, NULL);
</FONT></TT></PRE>
becomes
<PRE><TT><FONT COLOR="#990000"> SetForegroundWindow(hDlg);
TrackPopupMenu(hSubMenu, TPM_RIGHTBUTTON, pt.x,pt.y, 0, hDlg, NULL);
PostMessage(hDlg, WM_NULL, 0, 0);
</FONT></TT></PRE>
Refer to KB article "PRB: Menus for Notification Icons Don't Work Correctly" for more info.
<br>
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