How do I pass a hashtable to a scriptblock? - powershell

Question

I tried to pass a hashtable to a scriptblock like this where $arg3 is my hashtable. However, it failed. How do I do it in the correct way?
It doesn't seem like it is passing anything to the script block.
$commandParameters.ComputerName = $ComputerName
$commandParameters.ScriptBlock = {
param(
[Parameter()]
[switch]$arg1 = $false,
[Parameter()]
[array]$arg2,
[Parameter()]
[hashtable]$arg3
)
enter code here
Doing something here
}
Invoke-Command #commandParameters -ArgumentList $arg1, #($arg2), $arg3
=================================================================
I found the answer myself and it works for me. This is how I build the associative array and then pass it to the script block.
I am not sure why, but I was using the dot notation ($hash.a.b) to reference the hash table in a function and it works, but it doesn't work for a script block. It looks like I need to use [ ] (e.g. $hash[a][b])in the script block.
$compADGroups = #{}
foreach ( $adGroup in $adGroups ) {
if ( $compADGroups.$computerNameGroup -eq $null ) {
$compADGroups[$computerName] = #{}
$compADGroups[$computerName]["Group"] = #{}
$compADGroups[$computerName]["Group"] = $hashString
}
}
$session = New-PSSession -ComputerName 'Computer1'
Invoke-Command -Session $session -ArgumentList $compADGroups -ScriptBlock { param($compADGroups) $compADGroups[$env:computername]["Group"]}
Get-PSSession | Remove-PSSession

Answer 1

Make sure you're using Invoke-Command correctly.
$ScriptBlock = {
param(
[Parameter(Mandatory=$True, Position=1)]
[hashtable]$myHashTable
)
# Code here
}
Invoke-Command -ScriptBlock $ScriptBlock -ArgumentList ([hashtable]$hashtable)
If you specify certain arguments for a scriptblock, make sure you also describe the position value, and more often than not whether it's mandatory. If you are trying to pass your hashtable in as the second argument in an implicitly defined array of arguments, write your scriptblock so that it takes the hashtable at that specific position.
For example,
$ScriptBlock= {
param(
[Parameter(Position=2)] # Take note of the position you set here
[hashtable]$myHashTable,
[Parameter(Position=1)]
[string]$myString,
[Parameter(Position=3)]
[int]$myInteger
)
# Do stuff
}
Invoke-Command -ScriptBlock $ScriptBlock -ArgumentList ($myString, $myHashTable, $myInteger);
# ^ variable is in second position