Why can't I dispose my source FileSystemWatcher object? - powershell

Question

I have a FileSystemWatcher Script which does create a FileSystemWatcher for each Subfolder that matches a regex. This works like a charm.
Here's my script
$Folders = gci $Dir -Dir | ? Name -match '^\d{5}$' | % {
$source = $_.FullName
$watcher = [System.IO.FileSystemWatcher]::new()
$watcher.IncludeSubdirectories = $false
$watcher.Path = $source
$watcher.Filter = "*.csv"
$watcher.EnableRaisingEvents = $true
New-Variable -Name $_.Name -Value $watcher
}
$action = { stuff }
Get-Variable | ? Name -match '^\d{5}$' | % {
Register-ObjectEvent $_.Value Created -Action $action -SourceIdentifier $_.Name > $null
}
This leaves me with some FileSystemWatchers in different Variables like $70447, $78900, $13450 etc.
but I also have one watcher in $watcher, but this variable is only used to pass my FileSystemWatcher Object to the "productive" 5-digit variables
I wanted to get rid of $watcher by doing a $watcher.dispose() after the New-Variable Command. But when I do this, all of my watchers throw an error.
Why does this happen? $watcher is not in use anymore since the object is already passed on to a new variable. Can someone explain this?
Thanks!
Edit:
Register-ObjectEvent : Cannot access thrown Object.
Objektname: "FileSystemWatcher".
In Z:\Powershell-Scripts\FSW.ps1:43 Zeichen:5
+ Register-ObjectEvent $_.Value Created -Action $action -SourceIden ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.IO.FileSystemWatcher:FileSystemWatcher) [Register-ObjectEvent], ObjectDisposedException
+ FullyQualifiedErrorId : INVALID_REGISTRATION,Microsoft.PowerShell.Commands.RegisterObjectEventCommand

Answer 1

If I had to guess, the references are getting tied to the variables somehow and disposing is causing some kind of scope issue. I'm unable to replicate your problem, but consider not having in-between variable assignments and see if it resolves your issue:
Get-ChildItem -Path $dir -Directory | ? Name -match '^\d{5}$' | % {
New-Variable -Name $_.Name -Value (New-Object -TypeName System.IO.FileSystemWatcher -Property #{
IncludeSubdirectories = $false
Path = $_.FullName
Filter = '*.csv'
EnableRaisingEvents = $true
})
}
$action = { stuff }
Get-Variable | ? Name -match '^\d{5}$' | % {
$null = $_.Value | Register-ObjectEvent -EventName Created -Action $action -SourceIdentifier $_.Name
}