Shell Extension to Copy Full Filename Path(s)

A single file selection…
Shell Extension to copy path of filename

Multiple files selected…
Shell Extension to copy path of
filename

Environment: VC6 SP3, NT4 SP5, IE5

There numerous times that I’ve wished I could simply right-click on a
file, and copy its full pathname in order to paste it into an e-mail or
a file open dialog. I finally decided to write it
myself and thought someone else might find it useful. The extension adds
a ‘Copy Path’ command to the context menu for a single file/folder
selection and a ‘Copy All Paths’ command for multi-file/folder selection.
For a single selection the complete pathname of the file is simply
placed on the clipboard. For a multi-file selection, all the paths of
the files are placed on the clipboard separated by <cr><lf>
pairs.

One unexpected ‘feature’ is that you can right-click on a shortcut and the
path of the target will be copied to the clipboard. Of course, the
shortcut can be anywhere, including shell menu items if the IE4
active desktop option is installed.

Some of the code was based on code written by Dino Esposito from his book,
Visual C++ Window Shell Programming (Wrox). This is an excellent
resource for shell programming. I’ve run across a few things that his
book didn’t cover and found a bug related to a newer version of IE (I
think).

This has been tested only on NT4 SP5 with IE5, and 95 without IE.

Overview

This is not a tutorial on shell extensions. I’ll just give a brief
overview of the requirements for a shell
extension with some specifics about this example. There are several good
resources,
one of the best of which is the book I mentioned earlier by Dino Esposito,

Visual C++ Window Shell Programming
. Chris Losinger also has an
example,
Shell Extension Context Menu Sample
at CodeGuru.

I started building this component by simply creating an ATL COM
project, and then adding a simple ATL object. I then added the necessary
interfaces and their implementations. A shell extension requires
implementation
of two interfaces, IShellExtInit and IContextMenu.

IShellExtInit has only one
method, Initialize which is used to get the name of the files that
have been selected (this extension only gets the name of the file
with the current focus, although it could be expanded to be disabled if
multiple files were selected, or to put all the paths on the clipboard.)

IContextMenu has three methods to implement, GetCommandString,
InvokeCommand, and QueryContextMenu.

  • QueryContextMenu is called when the extension is first loaded to
    get the text and ID for the context menu item.
  • InvokeCommand is called when the user invokes the menu item.
  • GetCommandString can be called in different situations, but for this
    example we only care
    when it is called to get the help text associated with the command.

    I had a bit of trouble getting this to work correctly and I think it
    has to do with most recent IE installation. Following is the code
    for GetCommandString:

    
    // IContextMenu::GetCommandString
    HRESULT CCopyPathExt::GetCommandString(UINT /*idCmd*/, UINT uFlags,
     UINT* /*pwReserved*/, LPSTR pszText, UINT cchMax)
    {
     try {
      USES_CONVERSION;
       // We don't care about the command ID, since we have a
       // single item
    
       // This is rather funky, but GCS_HELPTEXTA refers to a
       // single bit (4) and GCS_UNICODE refers to single bit
       // (1), but GCS_HELPTEXTW is a combination
       // of those values (5).  This works on both NT and 95.
       if ( uFlags & GCS_HELPTEXTA ) {
        // I'm assuming that this value always contains the number
        // of bytes available for the message, just to be safe.
        // So half it for Unicode characters.
        const int cChars = cchMax / sizeof(TCHAR);
    
        // Create some storage on the stack for building the
        // help text
        LPTSTR szHelpText =
         reinterpret_cast( _alloca( cChars ) );
    
        memset( szHelpText, 0, cChars );
    
        // Create a generic version of the help text depending on
        // the number of file selected
        if ( 1 == m_cFiles ) {
         _sntprintf( szHelpText, cChars - 1,
          _T("Copy full path of file to clipboard (%s)"), m_szFile);
        } else {
         const LPTSTR szMultiFileHelpText =
          _T("Copy full paths of selected files to clipboard");
    
         _tcsncpy( szHelpText, szMultiFileHelpText, min(cChars - 1,
          _tcslen( szMultiFileHelpText ) ) );
        }
    
        // Do character conversion depending on flag
        if ( uFlags & GCS_UNICODE ) {
         wcsncpy( reinterpret_cast(pszText),
          T2W(szHelpText), cChars );
        } else {
         strncpy(pszText, T2A(szHelpText), cchMax);
        }
       }
      } catch ( ... ) {
      return E_FAIL;
     }
     return S_OK;
    }
    
  • Most examples simply test for the bits GCS_HELPTEXTA or GCS_HELPTEXTW,
    but the value of GCS_HELPTEXTW is actually 5, not a single
    bit value, which is also equal to GSC_HELPTEXTA|GCS_UNICODE. So, I
    simply test for GCS_HELPTEXTA and then test for the GCS_UNICODE bit.
    I also assume that if GetCommandString requests a Unicode string,
    then the max length of the string is half of what it would normally
    be. This may be incorrect, but it’s a safe guess.

Future work

  • There are ‘extended’ commands for the shell that are displayed when
    the user holds down the SHIFT key. For example, under NT, you’ll get
    the additional commands ‘Compress’, ‘Uncompress’, and ‘Open With…’
    (even if the file already has an association). I would like to add
    extended commands that only copy the filename(s) not the path (fewer
    keystrokes than F2, Ctrl-C, ESC). The documentation for
    IContextMenu::QueryContextMenu
    states that the CMF_EXTENDEDVERBS “…is set when the calling
    application
    wants extended verbs. Normal verbs are displayed when the user right-clicks
    an object. To display extended verbs, the user must right-click while
    pressing the SHIFT key.”
    But, I could not get this to work nor find
    any examples. Let me know if you know how to do this.
  • The bitmap for the icon gets XORed by the shell to make it look darker
    than it should. I’ve read that IContextMenu3 needs to be implemented
    to handle an ownerdraw menuitem in order to make the icons like
    as nice as the ‘Send To’ icons. A fix for this would be nice.
  • Finally, I would like to put together an ATL Object wizard to help
    jumpstart the creation of these shell extensions. I’ll do it if someone
    requests it.

Downloads

Download source and DLL – 87 Kb

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