<#
.SYNOPSIS
This script obtains the UpdateID of the Windows update program based on scanning local computer.

.DESCRIPTION
This script use Windows Update Agent API online scan or offline scan (if wsusscn2.cab is downloaded) to get availables update and it's UpdateId.

.INPUTS
The script takes no parameter.

.OUTPUTS
List of UpdateIDs and titles for update programs.

.EXAMPLE
# Online scan
.\get-updateidsbyscan.ps1

.EXAMPLE
# Offline scan (you have to run as administrator)
$ProgressPreference = 'SilentlyContinue'
Invoke-WebRequest -uri "https://catalog.s.download.windowsupdate.com/microsoftupdate/v6/wsusscan/wsusscn2.cab" -outfile "$env:userprofile\Downloads\wsusscn2.cab"
$ProgressPreference = 'Continue'
.\get-updateidsbyscan.ps1

.NOTES 
This script is a sample. Use it at your own risk.

#>
$scancabPath = "$env:userprofile\Downloads\wsusscn2.cab"
$UpdateSession = New-Object -ComObject Microsoft.Update.Session
if (Test-Path $scancabPath) {
  $UpdateServiceManager = New-Object -ComObject Microsoft.Update.ServiceManager
  $UpdateService = $UpdateServiceManager.AddScanPackageService("Offline Sync Service", $scancabPath)
  $UpdateSearcher = $UpdateSession.CreateUpdateSearcher()
  $UpdateSearcher.ServerSelection = 3 # ssOthers
  $UpdateSearcher.ServiceID = [string] $UpdateService.ServiceID
} else {
  $UpdateSearcher = $UpdateSession.CreateUpdateSearcher()
}

$searchResult = $updateSearcher.Search("IsInstalled=0 and Type='Software' and IsHidden=0")
if ($searchResult.Updates.Count -eq 0) {
  Write-Host "There are no applicable updates."
} else {
  $i = 0
  foreach ($update in $searchResult.Updates){
    $i++
    Write-Host $i">" $update.Title
    Write-Host "   Suport URL:" $update.SupportUrl
    Write-Host "   Update ID :" $update.Identity.UpdateID
    Write-Host ""
  }
}