Pass variables to function - powershell

Question

I have 2 functions. The functions need to pass a few earlier declared variables like this:
Function variable1, variable2
Now I've tried doing param with [ref] without success.
Here's the code for one of the functions. In this case the variables that are declared earlier are $wincluster and $vmhostwin.
function deploytemplatewin {
foreach ($image in $winimage) {
$templatename = $image, $wincluster -join "_"
$vcdatastore = $vc + "_vm_template_01"
try {
Get-Template $templatename -ErrorAction Stop;
$TemplateExists = $true
} catch {
$TemplateExists = $false
}
if ($TemplateExists -eq $false) {
Write-Log -Message "$($templatename) template was copied to cluster $($wincluster) on vCenter $($vc)"
New-VM -Name $templatename -VMHost $vmhostwin -Datastore $vcdatastore -Location (Get-Folder -Name WinTemplates) |
Set-VM -ToTemplate -Confirm:$false
} elseif ($TemplateExists -eq $true) {
Write-Log -Message "Template $($templatename) already existed in cluster $($wincluster) on vCenter $($vc)"
}
}
}
Worst case, I can explicitly state the variables in the function and it works.

Answer 1

If you want a function with parameters you need to define the parameters. You may also want to use the canonical Verb-Noun form for your function name (see here for a list of approved verbs).
Simple approach:
function Deploy-WindowsTemplate($Cluster, $VMHost) {
foreach ($image in $winimage) {
$templatename = $image, $Cluster -join "_"
...
}
}
More advanced approach:
function Deploy-WindowsTemplate {
[CmdletBinding()]
Param(
[Parameter(Mandatory=$true)]
[string]$Cluster,
[Parameter(Mandatory=$true)]
[string]$VMHost
)
foreach ($image in $winimage) {
$templatename = $image, $Cluster -join "_"
...
}
}
If you want you could also go without parameters and use the automatic variable $args, although I wouldn't recommend that.
function Deploy-WindowsTemplate {
foreach ($image in $winimage) {
$templatename = $image, $args[0] -join "_"
...
}
}
Note, however, that when calling a function parameter/argument values are separated by whitespace, not commas. They can be passed as positional parameters (by default in the order the parameters were defined)
Deploy-WindowsTemplate $wincluster $vmhostwin
or named parameters
Deploy-WindowsTemplate -Cluster $wincluster -VMHost $vmhostwin
Comma-separated values are passed as a single array argument.
Deploy-WindowsTemplate $wincluster, $vmhostwin
# ^^^^^^^^^^^^^^^^^^^^^^^
# one argument!