running remotely ps commands

Question

i have written a script which acts like a gpo editor, it can get some GPO and OU and link them or unlink them depending on user's wish. now this script does work when its running on Domain Controller machine but i need it to run on a windows 10 machine workstation on the domain. so i need to do the adjusment while showing the user the GUI, all the code must invoke the commands on the dc. i dont know whats the problem but when i enter the commands manually one by one it works and when its running as a script i get errors: for example here is a function for a link button . (i have a gui with 2 listboxes. one showing the GPO's and one showing the OU (the ou is shown as CanonicalName and not as Distinguishedname hence the $SWITCH variable to go back and forth so the user will see it in a more friendly way)

function LinkFn {
$ResultsTextBox.clear()
#This $SWITCH is used to Translate the user selection from the OU listbox from canonical back to distinguishedname 
$SWITCH = Get-ADOrganizationalUnit -filter *  -Property CanonicalName | Where-Object {$_.CanonicalName -eq $listBox2.SelectedItem}

    ForEach ($line in $listBox1.selecteditems){
         try {
             Invoke-Command -ComputerName "$DCNAME" -ScriptBlock {New-GPlink -name $line -target $SWITCH -ErrorAction STOP | Out-null}
             $ResultsTextBox.AppendText("`n GPO: $line HAVE BEEN LINKED Successfully.`n") 
            }
            catch{
            $ResultsTextBox.AppendText("`n$line ALREADY LINKED! TO THIS OU `n")
    }}}

can someone help?

From what i see, i think there is a problem with the code line:

$SWITCH = Invoke-Command -ComputerName "$DCNAME" -ScriptBlock {Get-ADOrganizationalUnit -filter *  -Property CanonicalName | Where-Object {$_.CanonicalName -eq $listBox2.SelectedItem}}

$switch is coming up empty (where it runs fine on dc), any idea why?

Answer 1

write your try catch block like below. You have to use $using:variable to use the variables declared outside of the scriptblock.;

try {
    Invoke-Command -ComputerName "$DCNAME" -ScriptBlock {New-GPlink -name $using:line -target $using:SWITCH -ErrorAction STOP | Out-null}
    $ResultsTextBox.AppendText("`n GPO: $line HAVE BEEN LINKED Successfully.`n") 
}
catch{
    $ResultsTextBox.AppendText("`n$line ALREADY LINKED! TO THIS OU `n")
}

Also, if the user does not have access to connect / remote to the DC, this wont work. User running the script will need admin level access to the DCs or use credentials for account that actually have access.