Monday, 13 August 2012

Adding Windows 7 TaskBar Support

The new MFC (10) has built-in support for the Windows 7 TaskBar.  A lot of people are using Windows 7 now so I thought I better update HexEdit to take advantage of the new features.  In particular I wanted to add support for:
  1. thumbnails that appear when you hold the mouse over a TaskBar button
  2. for progress display when HexEdit is performing a long task
  3. for the task list that is shown when you right-click the taskbar button

I describe my success with these below but first look at some general issues I first had to solve.

MFC 10 and Windows 7

The first thing you need to use the Windows 7 TaskBar is an App Id.  I just added a resource string with ID of AFX_IDS_APP_ID and MFC found it automatically.  You can actually let MFC create the App ID from other resource strings but this way I could set it to exactly what I wanted (ECSoftware.HexEdit.Free.40).

The other things you need to do to get access to all the new features of MFC is to set WINVER to 0x0601.  (It was previously 0x0501.)  By itself this will allow MFC to take advantage of Windows 7.  (I have no idea why internally Windows 7 is actually 6.1)

However, setting WINVER to a value greater than 0x501 (version number for XP) may cause some things to not work if the software is to run under Windows XP.  And I still want it to run on XP!  For example, the Windows headers make the structure NONCLIENTMETRICS 4 bytes larger for Vista and later (WINVER >= 0x0600) so I check at run-time what version of Windows is running and adjust the size of the structure before passing it to SystemParametersInfo().

Furthermore, I still want the code to build under Visual Studio 2008 (MFC 9) since not everyone has VS2010.  So some of the code needs to be conditionally-compiled using the _MFC_VER macro.  (Of course if you build HexEdit with VS2008 then you will not get the new MFC 10 features.)


Some sample MFC 10 applications support thumbnails so I thought it would be easy to add.  I eventually got it working (see screen shot) but it took me a while to work out how to add this to an existing MFC application.

Eventually, I worked out that I only had to call EnableMDITabbedGroups() at startup, magically even showing multiple thumbnails if there were multiple file open in HexEdit.  Moreover, there were extra features such as options for a close button on tabs, coloured tabs, etc.  Even better the new tab system added the ability to create vertical and horizontal tab groups and easily move windows between them (like MS first added to Visual Studio 2005).

There were some problems that I needed to work out though such as getting my tab context menus to work again.  This was actually quite easy and even continued to allow the context menu to be customizable (which is actually not a feature of any of the sample applications).  Also the tip window (which shows the associated file name when you hold the mouse over a tab) worked simply by setting an option.

It was not till much later that I found a big problem.  The Next Window command no longer worked.  This command has been in HexEdit from the start and allows you to cycle through all the open windows.  It is particularly useful in keystroke macros.  Internally there was now a tab "window" at the same level as the MDI windows meaning that my Windows API call to "get next window" code failed.  This was not too hard to fix once I understood the problem.

I also noticed that the Cascade/Tile etc options on the Window menu now do not do anything at all, so I disable them if the new MDI tabs are on.  (There is an option to use the old style tabs.)


Windows 7 has a cool feature where if a program is performing a long task it can show a green progress band as a background to the taskbar button.  This allows you to go and do something else when your program is busy but keep an eye on the progress by simply checking the taskbar button.

When working with large files HexEdit can take a long time to perform some operations, so this is the perfect application for the new Windows 7 TaskBar progress feature.  To add this change was trivial since HexEdit already supports a progress bar in the status bar.  It was a simple matter to add 4 lines to the function that already handles the progress display to get the Windows 7 progress to work.

Jump List

Encouraged by how easy the previous addition was I jumped straight into adding a custom jump list.  However, I soon found that this was no easy task at all.

First I should explain that the jump list is a list of options you see when you right-click on a TaskBar button - usually this is just a list of recently opened files.  The list is retained and available even when the software is not running.  By default MFC will give you a list of recently opened files, but I wanted three sections:

  • Recently Open Files
  • Commonly Opened Files
  • Favorites (indicated in HexEdit by adding to the Favorites category)

After a lot of reading and experimenting I could not work out how to get it to work.  There are some articles on using the new CJumpList class on MS various MS websites but they all contain mistakes or are incomplete.

None of the included MFC samples demonstrated the the CJumpList class and a search of the Internet reveal no complete samples except for the one at  But there was no way to download the complete project for this apart from tediously extracting one file at a time.  I tried various FireFox and IE add-ons such as PimpFish but all were useless for just downloading the project files.

Eventually I managed to download all the files for the sample using the Expression Web "Import Site Wizard".

With the help of this project I believe I now know more about how jump lists work and the problems I previously encountered.  One of the problems is that for a file to be added to the jump list the software must be registered to be able to open that type of file.


As usual MFC makes some things really easy and some things really hard.  (Most of the time things are easy once you work out how to do them which itself can be hard.)

I have added the code for the thumbnails and progress and committed the changes to the SourceForge repository.  Unfortunately these changes were added after the release of HexEdit 4.0 but you can get them try them if you want to build HexEdit yourself.  Otherwise you will have to wait till I release HexEdit 4.1.

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