How to Implement a Mouse Hover/Leave Message on the System Tray


Full Text Search: The Key to Better Natural Language Queries for NoSQL in Node.js


This article illustrates how to implement a tray mouse hover/leave message.

The Problem

Some programs want to get a mouse hover/leave message from the system tray when they want to show a popup window that is not a tool tip. However, the Windows shell doesn't support it. We can only get mouse move, up, down, and double-click messages from the system tray.

It is very easy to implement a WM_MOUSEHOVER message because the first WM_MOUSEMOVE is that. But, WM_MOUSELEAVE is hard to implement, so I decided to write a compact class to notify the window of a mouse hover/leave message.

The Idea

The basic idea is very simple. It is that no WM_MOUSEMOVE message fires when the mouse is out of the tray icon. This class saves the mouse point whenever a WM_MOUSEMOVE message fires on the system tray, and then another thread compares it with the current mouse point. The thread fires a WM_MOUSELEAVE message when the two points are different.

The following code is the WM_MOUSEMOVE handler.

VOID CTrayPos::OnMouseMove()

   if(m_bTrackMouse == FALSE)
      m_bTrackMouse = TRUE;


This is a thread function that checks the mouse point.

UINT CALLBACK CTrayPos::TrackMousePt(PVOID pvClass)
   POINT       ptMouse;
   CTrayPos    *pTrayPos = (CTrayPos *) pvClass;

   while(WaitForSingleObject(pTrayPos->m_hExitEvent, 2000) ==

      if(pTrayPos->m_bTrackMouse == TRUE)

         if(ptMouse.x != pTrayPos->m_ptMouse.x || ptMouse.y !=
            pTrayPos->m_bTrackMouse = FALSE;

   return 0;

Using the Code

If you want to use this class in your project, just follow these simple steps.

  • Add traypos.h and traypos.cpp file to your project.
  • Declare a variable of this class like that.
    Note that this class instance exists until the tray icon is deleted, so you must declare it a member variable or a global variable.
  • CMsgTrayPos traypos;
  • Add the following code after the register tray by calling Shell_NotifyIcon.
    The three parameters—hwnd, uID, and uMsgID—are the same value as the member of NOTIFYICONDATA.
  • traypos.SetNotifyIconInfo(hwnd, uID, uMsgID);
  • Call CMsgTrayPos::OnMouseMove on your WM_MOUSEMOVE message handler from the system tray.
  • Now, you can add WM_MOUSEHOVER and WM_MOUSELEAVE messages to your tray message handler and write a code there.

CMsgTrayPos API

  • VOID CMsgTrayPos::SetNotifyIconInfo(HWND hwnd, UINT uID, UINT uCallbackMsg);
    This function provides tray icon inforamtion to the class. The three parameters—hwnd, uID, and uCallbackMsg—and members of NOTIFYICONDATA are the same.
  • VOID CMsgTrayPos::OnMouseMove()

  • This function is very important. You must call this function when you get a WM_MOUSEMOVE message from the system tray.
    This function checks the mouse hover status and updates the mouse point internally.
  • BOOL CMsgTrayPos::IsIconHover();
    This function returns the mouse hover status. It returns TRUE if your mouse is on your tray icon.


  • 22 Aug 2004—Initial upload.



  • Nice legs

    Posted by Artipol on 07/22/2008 06:05am

    That girl has a very nice-looking pair of legs.

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • A CRM solution holds a wealth of information and document generation tools allow users to take that information and create documents with both visual appeal and function. Document generation is the process of automatically producing a file and document generation applications save companies time, mistakes, and money. You bought Salesforce to be more efficient — why are you still manually creating proposals, contracts, invoices, and account plans? Read this eBook to learn how you can automate virtually …

  • Cloud has the potential to offer many benefits that can enable great success within your business. However, there are still many myths floating around about backing up to the cloud. In this eBook, you'll discover the truth about five of the most common cloud myths, including myths about security, maintaining regulatory compliance and more. Get to the truth, so you can backup to the cloud with confidence.

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date