Using variables outside a function - windows

Question

I am currently writing my first script in Powershell and I am already facing the first problem.
I would like to read the value from a variable in a function so that I can use this variable in another cmd-let later. The problem now is that the variable is only recognized inside the function block and not outside.
How do I get this to work?
Thanks for the help :-)
function Write-Log([string]$logtext, [int]$level=0)
{
if($level -eq 0)
{
$logtext = "[INFO] " + $logtext
$text = "["+$logdate+"] - " + $logtext
Write-Host $text
}
}
Send-MailMessage -To "<xxx#xxx.de>" -Subject "$text" -Body "The GPO backup creation was completed with the following status: `n $text" -SmtpServer "xxx#xxx.de" -From "xxx#xxx.de"
I would like to submit $text

Answer 1

This has to do with variable scoping behavior in PowerShell.
By default, all variables in the caller's scope is visible inside the function. So we can do:
function Print-X
{
Write-Host $X
}
$X = 123
Print-X # prints 123
$X = 456
Print-X # prints 456
So far, so good. But when we start writing to variables outside the function itself, PowerShell transparently creates a new variable inside the function's own scope:
function Print-X2
{
Write-Host $X # will resolve the value of `$X` from outside the function
$X = 999 # This creates a new `$X`, different from the one outside
Write-Host $X # will resolve the value of the new `$X` that new exists inside the function
}
$X = 123
Print-X2 # Prints 123, and 999
Write-Host $X # But the value of `$X` outside is still 123, unchanged
So, what to do? You could use a scope modifier to write to the variable outside the function, but the real solution here is to return the value from the function instead:
function Write-Log([string]$logtext, [int]$level=0, [switch]$PassThru = $true)
{
if($level -eq 0)
{
$logtext = "[INFO] " + $logtext
$text = "["+$logdate+"] - " + $logtext
Write-Host $text
if($PassThru){
return $text
}
}
}
$logLine = Write-Log "Some log message" -PassThru
Send-MailMessage -Subject $logLine ...

Answer 2

if you need to access a variable outside a function in Powershell you might need to use the global variable.
$global:myglobalvariable="This is a PowerShell global variable"
or if its a null
$global:myglobalvariable2 = $null