GetForegroundWindow doesn't work on xp

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Carlos - 07 Nov 2007 16:34 GMT

I can not get

[ DllImport("user32.dll") ]
public static extern IntPtr GetForegroundWindow();

to work on windows xp, I always get null. It works fine on vista, I
just don't know why xp is failing.
Any ideas?
Thanks,

--Carlos

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Nicholas Paldino [.NET/C# MVP] - 07 Nov 2007 16:44 GMT

Carlos,

Can you provide an example? The declaration looks fine, so it probably
has something to do with where you are calling it.

Signature

- Nicholas Paldino [.NET/C# MVP]
- mvp@spam.guard.caspershouse.com

>I can not get
>
[quoted text clipped - 7 lines]
>
> --Carlos

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Carlos - 07 Nov 2007 17:08 GMT

On Nov 7, 10:44 am, "Nicholas Paldino [.NET/C# MVP]"
<m...@spam.guard.caspershouse.com> wrote:

> Carlos,
>
[quoted text clipped - 16 lines]
>
> > --Carlos

There is a lot of code involved with this, I'll see if I can make a
small example. I did forget to mention one more thing, I am working on
a taskbar replacement, is there a chance it has to do with that?

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Carlos - 07 Nov 2007 17:26 GMT

On Nov 7, 10:44 am, "Nicholas Paldino [.NET/C# MVP]"
<m...@spam.guard.caspershouse.com> wrote:

> Carlos,
>
[quoted text clipped - 16 lines]
>
> > --Carlos

Could it maybe have something to do with what this MS article
discusses:

http://support.microsoft.com/kb/118624

GetForegroundWindow() is documented to return the handle of the
foreground window, that is, the window that the user is currently
working with. The proper handle is returned when the desktop that the
application is running on is active; however, when another desktop is
active, GetForegroundWindow() returns NULL.

This is expected behavior. There is no way to get the active window in
your own desktop while another desktop is active.

The application desktop is one desktop. Other desktops include the
logon and screen saver desktops. If GetForegroundWindow() returned a
handle to the logon dialog box, it would be possible to create an
application that could get user passwords. This would violate Windows
NT security.

For this reason, it is not possible to create screen savers that melt
or drop out.

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Ignacio Machin ( .NET/ C# MVP ) - 07 Nov 2007 18:00 GMT

Hi,

Yep, that seems to be the problem. Curiously you can do it now in Vista. At
least there is something better in Vista :)

Signature

Ignacio Machin
http://www.laceupsolutions.com
Mobile & warehouse Solutions.

> On Nov 7, 10:44 am, "Nicholas Paldino [.NET/C# MVP]"
> <m...@spam.guard.caspershouse.com> wrote:
[quoted text clipped - 42 lines]
> For this reason, it is not possible to create screen savers that melt
> or drop out.

Reply to this Message

GetForegroundWindow doesn't work on xp

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