CODEWITHSUNDEEP
powershellpowershell-2.0
Sunit
Sunit

Reputation: 519

PowerShell - SupportsShouldProcess within script property

I'm getting a null expression when I try to access a variable within the ShouldProcess script-block. This is what I have in a script method:

$scaObject = [PerfWorker.CmdLets.PSDbInfoFactory]::GetPSDbInfo($info, $false)
$oracleObj = [PerfWorker.CmdLets.OracleParamsDto]$scaObject
Add-Member -InputObject $oracleObj -MemberType ScriptMethod -Name DropSchemas -Value {      
    $oraWorker = [PerfWorker.CmdLets.PSDbOracleInfo]$this.DbWorker                         
    $args | foreach {                                                                       
        #Start getting error "You cannot call a method on a null-valued expression" from line below
        if($psCmdLet.ShouldProcess(                                       
            "Delete Oracle Schema $_ on $($this.Hostname)? This action cannot be undone!",  
            "Delete Schema?"))                                                              
        {
            $oraWorker.DropS3DSchemas($_)                                       
        }                                                                               
    }
}

If I remove the $psCmdlet.ShouldProcess block and just call the $oraWorker.DropS3DSchemas() method, then everything works fine.

Upvotes: 1

Views: 1607

Answers (1)

Keith Hill
Keith Hill

Reputation: 202032

You appear to be mixing the cmdlet execution context with the execution context of a script method on an object. The script method code is captured in a scriptblock that is run later outside the context of the cmdlet method that created it. Before the if check if $PSCmdlet -eq $null. I don't think you can do what you're trying to do here. The ShouldProcess() needs to execute in the context of your cmdlet. The PowerShell way would be to create a Drop-Schemas cmdlet that does the work. Then you can use the ShouldProcess() feature in that cmdlet.

Upvotes: 3

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