Script won't run in Switch menu - powershell

Question

function Show-Menu { #Create the Show-Menu function
param ([string]$Title = 'Functions') #Sets title
Clear-Host
Write-Host "`t6: Reboot History." -foregroundcolor white
Write-Host "`tQ: Enter 'Q' to quit."
} #close of create show menu function
#Begin Main Menu
do
{
Show-Menu #Displays created menu above
$Selection = $(Write-Host "`tMake your selection: " -foregroundcolor Red -nonewline; Read-Host)
switch ($selection) #Begin switch selection
{
#===Reboot History===
'6' {
$Workstation = $(Write-Host "Workstation\IP Address" -nonewline -foregroundcolor DarkGreen) + $(Write-Host "(Use IP for remote users)?: " -NoNewline; Read-Host)
$DaysFromToday = Read-Host "How many days would you like to go back?"
$MaxEvents = Read-Host "How many events would you like to view?"
$EventList = Get-WinEvent -ComputerName $Workstation -FilterHashtable #{
Logname = 'system'
Id = '41', '1074', '1076', '6005', '6006', '6008', '6009', '6013'
StartTime = (Get-Date).AddDays(-$DaysFromToday)
} -MaxEvents $MaxEvents -ErrorAction Stop
foreach ($Event in $EventList) {
if ($Event.Id -eq 1074) {
[PSCustomObject]#{
TimeStamp = $Event.TimeCreated
Event = $Event.Id
ShutdownType = 'Restart'
UserName = $Event.Properties.value[6]
}
}
if ($Event.Id -eq 41) {
[PSCustomObject]#{
TimeStamp = $Event.TimeCreated
Event = $Event.Id
ShutdownType = 'Unexpected'
UserName = ' '
}
}
}
pause
}
}
}
until ($selection -eq 'q') #End of main menu
Works perfectly fine if I remove the script from the switch and run it separately, but as soon as I call it from the switch it still asks for the workstation/IP, how many days, and max events, but just outputs nothing.
Here is what it looks like when it works:
How many days would you like to go back?: 90
How many events would you like to view?: 999
TimeStamp Event ShutdownType UserName
--------- ----- ------------ --------
12/23/2022 12:20:55 AM 1074 Restart Username
12/20/2022 1:00:01 AM 1074 Restart Username
12/17/2022 12:21:54 AM 1074 Restart Username
12/13/2022 8:57:40 AM 1074 Restart Username
This is what I get when I run it within the switch menu
Workstation\IP Address(Use IP for remote users)?: IP Address
How many days would you like to go back?: 90
How many events would you like to view?: 999
Press Enter to continue...:
I have tried just doing 1 day and 1 event, but same results. No errors or anything indicating a failure, so not sure how to troubleshoot this. I have had similar issues with switches in the past that were resolved with some researching into scopes, but I don't think this is the same case as it is all self contained within the switch itself.
I am at a loss, any ideas? As always, any insight into my script is greatly appreciated, even if it doesn't resolve the problem at hand.

Answer 1

JosefZ has provided the crucial pointer:
force synchronous to-display output with, such as with Out-Host
if you neglect to do so, the pause statement will - surprisingly - execute before the [pscustomobject] instances emitted by the foreach statement, due to the asynchronous behavior of the implicitly applied Format-Table formatting - see this answer for details.
Here's a simplified example:
switch ('foo') {
default {
# Wrap the `foreach` statement in . { ... },
# so its output can be piped to Out-Host.
. {
foreach ($i in 1..3) {
[pscustomobject] #{ prop = $i }
}
} |
Out-Host # Without this, "pause" will run FIRST.
pause
}
}
Note:
For Out-Host to format all output together it must receive all output from the foreach loop as part of a single pipeline.
Since foreach is a language statement (rather than a command, such as the related ForEach-Object cmdlet) that therefore cannot directly be used at the start of a pipeline, the above wraps it in a script block ({ ... }) that is invoked via ., the dot-sourcing operator, which executes the script block directly in the caller's context and streams the output to the pipeline.
This limitation may be surprising, but is rooted in the fundamentals of PowerShell's grammar - see GitHub issue #10967.
An all-pipeline alternative that doesn't require the . { ... } workaround would be:
1..3 |
ForEach-Object {
[pscustomobject] #{ prop = $_ } # Note the automatic $_ var.
} |
Out-Host