calling Invoke-Expression with Parameters in Powershell

Question

I\'ve written a powershell module in c# that has a bunch of cmdlets like

Add-VM

The cmdlets reach out to an API and pull data back.

but for the sake

Answer 1

That error is from Invoke-Expression not Add-VM and you just need quotes around the argument:

Invoke-Expression "Add-VM $argstr"

This has the drawback of forcing all objects into string format. This might be acceptable for simple types like ints and strings but if you want to pass through a more complex object it won't work. An alternative would be to splat the arguments with @args but I don't think you can do this through Invoke-Expression or Invoke-Command. You need to directly call the cmdlet:

function newtask {
    params([string]$command)

    switch ($command) {
        "addvm" { Add-VM @args }
        "deletevm" { Remove-VM @args }
    }
}

Answer 2

I know this is a little old now, but I was having a similar issue and a co-worker showed me that escaping $argstr prevents the object from getting converted to a string.

Invoke-Expression "Add-VM `$argstr"