Can a validation script alter the parameter itself?

by scottbass at 2013-03-04 23:14:05

Test script foo.ps1
Position = 0,
if ($.GetType().Fullname -like “System.IO.*”) {$ = $.Fullname}
$Path | % {$

# call using path (string)
.\foo.ps1 c:\temp\temp1

The “real script” will call GCI against the path string(s), retrieving the children.

# call using System.IO objects (either files or directories)
$files=gci c:\temp\temp1
.\foo.ps1 $files

In this second scenario, I need the full path to the file objects. If I just cast the System.IO objects to strings (by changing the parameter type declaration from [Object[]] to [String[]]), I get relative paths, and the GCI call later in the script fails.

Can reformatting of the input parameter be accomplished via a validation script?
by mjolinor at 2013-03-05 05:44:00
I don’t think so. The validation script block is going to run in it’s own scope. You can set a variable there, but that instantiates a new variable, and it goes away when the validation script finishes and the scope is disposed.