Loading display names in array

Question

Hi,
I would like comparing registry display names before and after a software installation.
So the function below is :
1. loading display names
2. Then I create manually a registry display names
3. I load again the display names
4. And I am running a comparison between previous and after installation.
The display names, I created is Vcredist2005. So the comparison should return Vcredist2005.
But I get only the last value of the arrays. Why??
Function Get-DisplayName {
Begin {
[string[]]$regKeyApplications = 'HKLM:SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall',
'HKLM:SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall'
Process {
[psobject[]]$installedApplication = @()
ForEach ($regKey in $regKeyApplications) {
$installedApplication += Get-ChildItem $regKey | foreach { Get-ItemProperty $_.PSPath } `
| select DisplayName `
| Where {$_.DisplayName -ne $null}| Sort-Object DisplayName
$installedApplication=$installedApplication | Sort-Object DisplayName
Write-Output $installedApplication
End {
$a=Get-DisplayName
$a.Count
#Add a false display name in the registry before continuing running.
#I added Vcredist2005
pause
$b=Get-DisplayName
$b.Count
Compare-Object -ReferenceObject $B -DifferenceObject $A
Thanks,

Answer 1

When you're using compare-object to compare objects you should specify the property you want to compare:
Try this:
Compare-Object -ReferenceObject $B -DifferenceObject $A -Property DisplayName
Inspired by Carlsberg.