Vista / Windows 7 Compliant, what does it really mean? When
installing on Vista / Windows 7, it is very much different than installing on
previous Windows versions. One main difference is writing to the
registry. Many locations are basically off limits for legacy or badly written applications and Vista will
perform "Registry Virtualization" which means that some registry
information that used to go to the registry will now go to your profile
on disk. Another change is that you should not install your app to the
"Program Files" folder unless it will not write any information in the
installed location. If it does you will need supervisory privileges to
do so. It is best to make your application as clean as possible and not
require supervisory privileges at all.
The most common area to install
your non-compliant app (Apps that cannot be changed) or a third party
pre-packaged legacy apps (apps that have the data files that the app
writes to in the same folder as the exe) in Vista is
"C:\Users\Public\YourAppName" There are no
restrictions to your app in this locations. This is especially true if
your app writes to the installed location and you cannot move the
database or file it writes to. Installing in this location; you can
allow your program to write to the file without having Administrator privileges; however you will lose Vista's protection for your app from
program modifications or deletions (virus, malware, hacking or just
plain stupidity). An application should never run "As Administrator" if
you can help it.
If your apps run in XP under a limited users account
they should run in Vista under the same. Strange as it might seem, I
have apps that run just fine in a Limited Users account in Vista but
not in a Limited Users account on XP (due to virtualization). It would seem that some software
applications attempts to change some off-limit registry location and therefore the app won't work.
Many times the main reason a properly constructed VB app won't work
under a Limited Users account is a permissions restriction on the
HKLM\Software\Classes\TypeLib key. The problem is that the user does
not have read access rights and therefore the app cannot instantiate
objects that have CSLID's that reside there. A simple fix is to change
the permissions under an administrator account for Read rights then
everything will work just fine under the limited users account.
I have
read on the internet in various forums that the All Users folder can't
be used. These people have no idea of what they are talking about!!!
Therefore it would not be a brilliant idea to listen to their opinions
on how to properly install an application; they truly have no idea or
very limited knowledge in this area. The All Users folder is writable, you just need
to create a folder in it then you can write you data into that folder.
What are these people thinking??? If everyone wrote their data to the
All Users folder without their own folder everyone would be over
writing over other apps data and files with the same name. Such idiocies...
Here are some tips to help you
create a Vista compliant app
If you have files in the installation
folder (C:\Program Files\YourAppName) that you read and do not write
to. Open the file with read only access. Opening files with write
access in a protected folder is asking for trouble with unexplained or
unexpected application crashes for unhandled errors. You should get the
application data path using a system API, create a folder then place
your data there. You will also need to change the file locations in
your app to point to these locations where you access the data that
needs to be written to disk.
Do not access the registry any more than
you need to and if you need to make sure it is not a protected part of
the registry (for writing). Most of the time it is easy to tell if the
location you want to access is protected. Create a limited users
account then log onto it, open RegEdit (Start->Run, then type in
Regedit) then go to the key where you want to write and look at the
permissions for the user "Everyone" (Right click on the key). If you
see the key in the Administrator account and don't see it in the
Limited Users account, you definitely cannot use that key. If you find
the key in the Limited Users account and you check the permissions and
there is no user "everyone" or the user "everyone" does not have at
least "Read" privileges then you can not use that registry key at all.
Remember that if you do not have privileges to any level of the
registry key above your key you will not have rights to that key. So if
you don't have "Write" privileges you cannot update that key and
attempting to write to it will give you a need for "Administrator
Privileges".
These few things alone will help you make a Vista compliant application
and keep you from cursing your new operating system. Well, sometimes...
Ralph James
