How to call a method with output parameters in PowerShell?

I'm working on a script to get started in PowerShell. I'm trying to convert a working VBScript script that enumerates mapped network drives on a remote Windows computer.

One of the tasks is to use remote WMI to read the registry and find the process owner of explorer.exe in order to determine who is logged in. This seems easy enough going by this guide.

However, the WMI method I need to call is GetOwner() from Win32_Process, which requires two output parameters to store its return value.

How can I call a method with output parameters? When I try to give it two strings, I get the error: Cannot find an overload for "GetOwner" and the argument count: "2".. The MSDN page says there are two parameters, so I'm not sure what I'm doing wrong.

Using the [ref] modifier:

SomeMethod( [ref] $a );

Notable blog entries

• http://geekswithblogs.net/Lance/archive/2009/01/14/pass-by-reference-parameters-in-powershell.aspx
• http://weblogs.asp.net/soever/archive/2009/03/26/powershell-return-values-from-a-function-through-reference-parameters.aspx

$explorer = gwmi Win32_Process -computerName computerName -filter "Name='explorer.exe' and SessionID=0"   
$explorer.GetOwner() | select user,domain