OpenEuphoria

1. Using Win32Lib's geFileInfo to show system icon

• Posted by Jonas Temple <jtemple at yhti.net> Jan 25, 2006
• 473 views

All,

I'm trying to use Win32Lib's getFileInfo() function to display the small icon
for a given file.  The trick here is the file is not on the PC.  According to
MSDN, if I use SHGFI_USEFILEATTRIBUTES with FILE_ATTRIBUTE_NORMAL then this
should give me the icon index even if the file doesn't exist.  Here's a code
snippet:

file_info = getFileInfo(trim(dir_data[i][2]),
   FILE_ATTRIBUTE_NORMAL,
   or_all({SHGFI_USEFILEATTRIBUTES,
           SHGFI_SYSICONINDEX,
           SHGFI_SMALLICON}))

Then this should return the handle/index of the small icon.  Once I have that,
how do I use addTVItem() to display this icon?  I can't seem to put these
together in my mind and was hoping someone has already done this.

Thanks!

Jonas Temple
http://www.yhti.net/~jktemple

3. Re: Using Win32Lib's geFileInfo to show system icon

• Posted by Larry Miller <larrymiller at sasktel.net> Jan 25, 2006
• 466 views
• Last edited Jan 26, 2006

Using the code you are using could cause problems, particularly if the code is
called many times and with Win98.

But there is an alternative you might consider. Win32Lib does maintain it's own
imagelist but you do not have to use it. You may be able to use the system
imagelist whose handle can be obtained with the following code:

file_info=getFileInfo("*.txt",#80,
     or_all({SHGFI_SYSICONINDEX+SHGFI_USEFILEATTRIBUTES+SHGFI_SMALLICON})

file_info[7] will contain the handle to the system imagelist.

You can then do:

void=sendMessage(MainTV,TVM_SETIMAGELIST,TVSIL_NORMAL,file_info[7])

to use this image list in the Treeview control.

Use the icon index returned by getFileInfo() directly in addTVItem()

But there are a number of things to remember when doing this. The system
imagelist is owned and managed by the system and should never be destroyed or
directly modified by the application. Doing this on Win98 will corrupt a vital
system resource and require a reboot. getFileinfo() will add any required images.
On NT platforms you will be working with a private copy of the real system
imagelist and no problems should result. But any direct modification of this list
is unsupported and discouraged by Microsoft.

This means that you can use only images in the system imagelist, you can not add
your own. If this is acceptable to your application then this would be a viable
alternative. There should be no concerns over resource usage and performance will
be much better. Adding an icon to an imagelist can be a time consuming operation.

I learned this from a lot of browsing MSDN & elsewhere and trial and error -
mostly error.

Larry Miller

5. Re: Using Win32Lib's geFileInfo to show system icon

• Posted by Larry Miller <larrymiller at sasktel.net> Jan 25, 2006
• 468 views
• Last edited Jan 26, 2006

Yes, setting a Treeview control to use the system imagelist will will not allow
the use of Win32Lib's imagelist for the treeview. For normal images a Treeview
can use only one imagelist at one time.

When Win32Lib adds an image to it's imagelist it checks for duplicate handles
but this may not help you much. I don't know how getFileInfo manages the image
handles that it creates and it probably varies on different systems. These image
handles are owned by the application and the system has no idea how they may be
used. If a new image is created for the same file or folder then Win32Lib will
add it to the list.

If the Treeview were created and the populated only once there should be no
problem. But if the same directories are repeatedly accessed and updated in the
treeview there will likely be problems over time, particularly with Win98. If I
knew more of what you were trying to accomplish I may be able to help more.

Larry Miller

7. Re: Using Win32Lib's geFileInfo to show system icon

• Posted by Greg Haberek <ghaberek at gmail.com> Jan 25, 2006
• 476 views
• Last edited Jan 26, 2006

> It's working now but I guess I need to figure out how to use both my cust=
om icons and icons from the system.  Here's a screen shot of the window:

Um... why not use a function that returns the handle to an icon, not
its image list index? Have you looked at ExtractAssociatedIcon?
There's a Win32Lib demo called icon00.exw. Here's a wrapper for the
function.

global constant
    xExtractAssociatedIcon = registerw32Function( shell32,
    "ExtractAssociatedIconA", {C_INT,C_POINTER,C_POINTER}, C_INT )

global function extractAssociatedIcon( sequence pFilename )

    atom mset, hInst, lpIconPath, lpiIcon, hIcon

    mset = w32new_memset()
    hInst = instance()
    lpIconPath = w32acquire_mem( mset, pFilename )
    lpiIcon = w32acquire_mem( mset, Word )

    hIcon = w32Func( xExtractAssociatedIcon, {hInst, lpIconPath, lpiIcon}=
 )

    w32release_mem( mset )

    return hIcon
end function

9. Re: Using Win32Lib's geFileInfo to show system icon

• Posted by Greg Haberek <ghaberek at gmail.com> Jan 26, 2006
• 474 views

> What I don't know is if identical icons are added to the list if they alr=
eady exist.  Could this potentially become a resource problem/leak?

Duplicate icons are not added to the list. And icon memory leaks exist
only on Windows 9x. I believe you're operating in a Windows 2k/XP
environment.