Dateiüberprüfung per Powershell - Versand per Mail

<#
     Monitor folder changes
#>

# Variables -------------------------
# local folder path to monitor
    $localFolderPath = "C:\Ordner"   
#Filename to check for changes
    $strFilename = "demo.txt"  
# interval to check for changes (seconds)
    $intMonitorInterval = 60
# -----------------------------------

# get seperate drive and path for wql query specific formatting
$strDrive = $localFolderPath.Split("\")  
$localFolderPath.TrimEnd("\")  
$strPath = $localFolderPath.Split(":")[1].Replace("\","\\")+"\\"  

# action fired when event occurs
$eventaction = {
    #object which fired the event
    $obj = $Event.SourceEventArgs.NewEvent.TargetInstance
    $objWMI = gwmi "Win32_OperatingSystem"  
    $modifiedDate = get-date ($objWMI.ConvertToDateTime($obj.LastModified)) -Format 'dd.MM.yyyy HH:mm:ss'  

    # send mail
    $smtpusername = 'USERNAME'  
    $smtppassword = 'PASSWORD'  
    $smtpfrom = 'fromuser@domain.de'  
    $smtpto = 'fromuser@domain.de'  
    $smtpserver = "smtp.server.de"  
    $smtpcred = new-Object pscredential($smtpusername,(Convertto-SecureString $smtppassword -AsPlainText -Force))
    Try{
     Send-MailMessage -To $smtpto -From $smtpfrom -Subject 'Eine Datei hat sich geändert' -Body "Die Datei '$($obj.Name)' wurde geändert am $modifiedDate" -SmtpServer $smtpserver -UseSsl -Credential $smtpcred -Encoding UTF8 -ErrorAction Stop  
     write-host "Datei '$strFilename' wurde geändert am $modifiedDate, eine E-Mail wurde verschickt." -ForegroundColor Green  
    }catch{
      write-host $_
    }
}

$query = "Select * From __InstanceModificationEvent WITHIN $intMonitorInterval`  
          where TargetInstance ISA 'CIM_DataFile'`  
          and TargetInstance.Drive = '$strDrive'`  
          and TargetInstance.Path = '$strPath'`  
          and TargetInstance.Name like '%$strFilename'"  

#actually register Event-Subscriber
Register-WmiEvent -query $query -SourceIdentifier "Monitor Folder Watcher" -action $eventaction  

while($true){
    sleep($intMonitorInterval)
}

# to unregister the event  call
# Unregister-Event -SourceIdentifier "Monitor Folder Watcher"