experience with VBScript on Vista needed

[Ken Ray]

Hey, Tiemo... 

> My questions are not going to my code, but to some principles with calling
> the shell wscript.exe

Are you using Rev 2.9 or later? If so, you don't need to call the shell()
command for VBScript; you can "do <script> as VBScript".

> 1.  I tried to catch any error from the get shell() command with "the
> result", "the syserror", "try -catch", but got never any error back from the
> shell, even if I have a wrong syntax in the VB, where the VB fails, the rev
> doesn't gets noticed. Which is the correct way to catch an error from a
> VBScript on the shell?

It should come back from the "shell" command. Here's an (old) example of
activating an application and trapping the result:

on VBS_AppActivate pTitle
  put format("set WshShell = WScript.CreateObject(\"WScript.Shell\")") into
tVBS
  put tVBS & cr & "WshShell.AppActivate" && quote & pTitle & quote into tVBS
  put "C:\vbs_temp.vbs" into tVBSPath
  put tVBS into url ("file:" & tVBSPath)
  set the hideConsoleWindows to true
  get shell("cscript.exe //nologo" && tVBSPath)
  put it into tResult
  if there is a file tVBSPath then
    send "delete file" && quote & tVBSPath & quote to me in 1 second
  end if
  if tResult <> "" then return "Error: " & tResult
end VBS_AppActivate

Here's how it would be done in Rev 2.9+:

on VBS_AppActivate pTitle
  put format("set WshShell = WScript.CreateObject(\"WScript.Shell\")") into
tVBS
  put tVBS & cr & "WshShell.AppActivate" && quote & pTitle & quote into tVBS
  put tVBS & cr & "result = Err.number" into tVBS
  do tVBS as "VBScript"
  put the result into tResult
  if there is a file tVBSPath then
    send "delete file" && quote & tVBSPath & quote to me in 1 second
  end if
  if tResult <> "" then return "Error: " & tResult
end VBS_AppActivate


> 2. Do I have to return explicity any error from the script back to rev, or
> will they passed to rev anyway? If yes, how and where?

See above...

> 4. Are there any experiences of windows installations without the scripting
> host? Perhaps the Home edition? If yes, how to check for that?

Well, according to my informaton, some form of Windows Script Host has been
included on all versions of Windows since Windows 98. You should check to
make sure that the VBScript you're calling is supported in the various
versions of Windows you need to support.

> 5. If every Vista version should have the windows scripting host, can it
> somehow be deactivated, so that my updater runs without result? If yes, how?

Not AFAIK. 

> 6. If the user clicks "cancel" while Vista is asking to allow this process,
> how can I get aware of this "cancel" in my rev app? Is there a chance to
> catch a "cancel" down from Vista level in my rev app?

I don't know, but I'd assume that the request happens *before* the script is
actually run, so you'd need to find a way to determine if your VBScript runs
or not. One way to do this might be for your Rev app to create a file and
have the VBScript change its contents or delete it. That way you could
detect "after" the script has run if the original file was still
there/unchanged. If so, the VBScript didn't run.

> 7. Are you aware of any other VBScript gotchas?

Yes - Some anti-virus software will bring up an alert dialog to the user
letting them know of a "potential malicious activity" if you try to
manipulate the file system with VBScript (basically any use of the
FileSystemObject), so that may make #6 above even more difficult.

Ken Ray
Sons of Thunder Software, Inc.
Email: kray at sonsothunder.com
Web Site: http://www.sonsothunder.com/