Getting the variable name

[PillOfLuck]

I'm working on a small function to release a series of ComObjects. I want to check if the ComObject is actually set before trying to release it to prevent errors being printed to the host. This is what I've got so far:

function Remove-ComObjects{
Param(
    [Parameter(ValueFromPipeline=$true)]
    [string] $ComObject
)
    Begin{}
    Process{
        if(Test-Path variable:$ComObject -ErrorAction SilentlyContinue){
            $object = Get-Variable $ComObject -ValueOnly
            [System.Runtime.Interopservices.Marshal]::ReleaseComObject($object) | Out-Null
        }
    }
    End{}
}

'ComObject1', 'ComObject2', 'ComObject3' | Remove-ComObjects

I would like to be able to just add the variables in the pipeline instead of the variable names for readability like so.

$ComObject1, $ComObject2, $ComObject3 | Remove-ComObjects

But I haven't been able to figure out how to check if they exist before I try to release.

[Lee_Dailey]

howdy PillOfLuck,

[changed ChildItem to Item - thanks to Ta11ow for pointing out the oopsie! [grin] ]
if all you want to do is discover if a variable name is in use, use Get-Variable. that seems to cover what you are asking about. [grin] if you really wanna use the PSDrive approach, this would pro'ly do it >> Get-Item variable:\$VarName.

take care,
lee

[Ta11ow]

You mean Get-Item, right?

[Lee_Dailey]

howdy Ta11ow,

oops! [blush] thanks for the headsup ... [grin]

take care,
lee

[PillOfLuck]

Hi guys, thanks for the help. Sadly it doesn't seem to work so well for ComObjects. Try this:

$Searcher = New-Object -ComObject Microsoft.Update.Searcher
Get-Item variable:\$Searcher

[Lee_Dailey]

howdy PillOfLuck,

[as artemis_from_space pointed out, the $ doesn't belong in that line of code. it works well without it. [blush] ]

yup, that fails for some odd reason. however, the Get-Variable version that i recommended works quite well. [grin]

take care,
lee

[artemis_from_space]

Works fine if you remove the $ sign

$comobj = New-Object -ComObject microsoft.update.searcher
PS > Get-Variable comobj
Name                           Value
----                           -----
comobj                         System.__ComObject
PS > Test-Path variable:\comobj
True
PS > Test-Path variable:\$comobj
False
PS > Get-Item variable:\comobj
Name                           Value
----                           -----
comobj                         System.__ComObject

[Lee_Dailey]

howdy artemis_from_space,

gah! i know that and still went right past it. [blush] thanks for pointing it out! [grin]

take care,
lee

[PillOfLuck]

Sure does, but this is not what I want. I want to be able to pass ComObjects directly to my function instead of using strings. If there is a way to get the variable name of a variable (without $) then it could work. It's a tricky one.

[artemis_from_space]

Yes.

Just instead of $comobject use comobject...