Best way to check if an PowerShell Object exist?

Question

I am looking for the best way to check if a Com Object exists.

Here is the code that I have; I\'d like to improve the last line:

$ie = New-Object -Co         


        

Answer 1

Incase you you're like me and you landed here trying to find a way to tell if your PowerShell variable is this particular flavor of non-existent:

COM object that has been separated from its underlying RCW cannot be used.

Then here's some code that worked for me:

function Count-RCW([__ComObject]$ComObj){
   try{$iuk = [System.Runtime.InteropServices.Marshal]::GetIUnknownForObject($ComObj)}
   catch{return 0}
   return [System.Runtime.InteropServices.Marshal]::Release($iuk)-1
}

example usage:

if((Count-RCW $ExcelApp) -gt 0){[System.Runtime.InteropServices.Marshal]::FinalReleaseComObject($ExcelApp)}

mashed together from other peoples' better answers:

• RCW & reference counting when using COM interop in C#
• RCW Reference Counting Rules != COM Reference Counting Rules
• “COM object that has been separated from its underlying RCW cannot be used” with .NET 4.0

and some other cool things to know:

• COM object that has been separated from its underlying RCW cannot be used
• Custom Marshaling
• Advanced COM Interoperability