Pass argument to Workflow (powershell) - powershell

Question

I know that you can't use Read-Host within a Workflow. But I need to prompt the user via Read-Host and then use that input data within a Workflow. We need to execute MSG.EXE on remote machines (since NetSend went bye bye)
I have this code. It runs without error but it does Not send any message. how do I pass my argument into the Workflow so it works?
$Computers = #("mg2014","cclab2","MG11751","mg10462","mg11768","mg11786","mg11741","mg13244","mg13434","mg14464", "mg10257")
workflow Test-WFConnection {
param(
[Parameter (Mandatory = $true)]
[object[]]$message
)
foreach -parallel ($computer in $computers) {
if (Test-Connection -ComputerName $computer -Count 1 -ErrorAction SilentlyContinue) {msg /SERVER:$computer * $msg}
}
}
$msg = Read-host "Enter your message here"
Test-WFConnection -message $msg
The issue is the $msg never gets sent to any machine.

Answer 1

To deal with workflows you have to understand the scopes in workflow. Here, the value of $msg is not with the scope thats why the value is not at all coming inside the block. So you have to use $Using:msg , then it will be available.
I will give a small example below to clarify your doubt:
workflow sample_test
{
$variable1 = 5
# Changes to variable value in an InlineScript do not affect
# the value of the workflow variable.
InlineScript {$variable1 = $Using:variable1 + 1; "Inline Variable1 = $variable1"}
"Workflow variable1 = $variable1"
# To change the value in workflow scope, return the new value.
$a = InlineScript {$variable1 = $Using:variable+1; $variable1}
"Workflow New variable1 = $variable1"
}
Below is the screenshot for your reference:
Hope it helps...!!!

Answer 2

How about you declare the computers in the workflow?
workflow send-message {
param(
[Parameter (Mandatory = $true)]
[string]$message
)
$computers = "mg2014","cclab2","MG11751","mg10462","mg11768","mg11786","mg11741","mg13244","mg13434","mg14464", "mg10257"
foreach -parallel ($computer in $computers){
if (Test-Connection -ComputerName $computer -Count 1 -ErrorAction SilentlyContinue){
msg /SERVER:$computer * $message
}}}
send-message -message (read-host 'Enter message')
This worked ok when I tested it.
As posted here: https://community.spiceworks.com/topic/1951356-pass-argument-to-workflow

Answer 3

you can pass the computers as parameter like this or is there any limitation that stops you from doing that:
$Computers = #("mg2014","cclab2","MG11751","mg10462","mg11768","mg11786","mg11741","mg13244","mg13434","mg14464", "mg10257")
workflow Test-WFConnection {
param(
[Parameter (Mandatory = $true)]
[object[]]$message,[object[]]$computers
)
foreach -parallel ($computer in $computers) {
if (Test-Connection -ComputerName $computer -Count 1 -ErrorAction SilentlyContinue) {msg /SERVER:$computer * $msg}
}
}
$msg = Read-host "Enter your message here"
Test-WFConnection -message $msg -computers $Computers

Answer 4

I'm not certain what is happening with these answers - they're a bit obscure.
Neal5's answer was the correct answer, but without actually explaining why (although I would also suggest adding the list of computers as a parameter as in Abhijith pk's answer).
The issue is the statement that is run if the condition is met:
if (Test-Connection -ComputerName $computer -Count 1 -ErrorAction SilentlyContinue) {
msg /SERVER:$computer * $msg
}
You're using $msg here, however you have named the parameter $message:
param(
[Parameter (Mandatory = $true)]
[object[]]$message
)
So you're statement should read:
msg /SERVER:$computer * $message