Variable showing null but not empty-CodePudding

Im trying to get remote registry key vaules using this script, it works fine but throws a few null errors on certain units, I'd like it to just output the error text if it can't find powershell 5.1 key.

*clients are win 7 HP, Workgroup *I know my logic is off (red if it's there, green if not) just trying to see what I can come up with myself before asking you guys for assistance

$ComputerName = get-content "C:\Users\David\Desktop\IPS.txt"
$Hive = 'LocalMachine'
$KeyPath = 'SOFTWARE\Microsoft\PowerShell\1\PowerShellEngine'
$Value = 'PowerShellVersion'

$KeyPath1 = 'SOFTWARE\Microsoft\PowerShell\3\PowerShellEngine'
$Value1 = 'PowerShellVersion'

    Foreach ($Computer in $ComputerName) {
        if (Test-Connection $computer -Count 2 -Quiet) {
            $reg = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey($Hive, $Computer)
            $key = $reg.OpenSubKey("$KeyPath")
            $Data = $key.GetValue($Value)
           
           
           $reg1 = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey($Hive, $Computer)
           $key1 = $reg1.OpenSubKey("$KeyPath1")
           $Data1 = $key1.GetValue($Value1)
  

If (($data = "2.0") -and ($Data1 = "5.1.14409.1005")){

Write-Host "$Computer needs updated " -ForegroundColor Red

##Added to try and do some error checking [string]::IsNullOrEmpty($Data1)
##Added to try and do some error checking Write-Host $Data1

}else {
Write-Host ""
Write-Host "$Computer        $Data" -ForegroundColor Green
Write-Host "$Computer        $Data1" -ForegroundColor Green 
Write-Host ""

} 
}
}

Error I'm getting:

it's weird cause I can output the variable and it looks fine.

CodePudding user response：

The error is occurring on line 18, which is:

$Data1 = $key1.GetValue($Value1)

Since the error indicates you are calling a method on a null-valued expression, that shows that the error has occurred because $key1 is null.

$key1, in turn, is expected to have a value after the previous line (17) is executed:

$key1 = $reg1.OpenSubKey("$KeyPath1")

OpenSubKey returns null when the operation failed. This would happen if the subkey did not exist. So your program needs to check whether $key1 is null after line 17. Then, instead of attempting to call a method on a null object, your program can put out an error message saying that the subkey could not be opened.

CodePudding user response：

If (($data = "2.0") -and ($Data1 = "5.1.14409.1005")){

The above is always true as you are doing assignments (=) vs testing (-eq).

Code should read:

If (($data -eq "2.0") -and ($Data1 -eq "5.1.14409.1005")){