How can I call explicitly implemented interface method from PowerShell?

Question

Code:

add-type @"
    public interface IFoo
    {
        void Foo();
    }

    public class Bar : IFoo
    {
        void IFoo.Foo()
        {
        }
    }
"@ -Language Csharp

$bar = New-Object Bar
($bar -as [IFoo]).Foo() # ERROR.

Error:

Method invocation failed because [Bar] doesn't contain a method named 'Foo'.

Answer 1

Bad news: It's a bug.

https://connect.microsoft.com/feedback/ViewFeedback.aspx?FeedbackID=249840&SiteID=99

Answer 2

I wrote something for PowerShell v2.0 that makes it easy to call explicit interfaces in a natural fashion:

PS> $foo = get-interface $bar ([ifoo])
PS> $foo.Foo()

See:

http://www.nivot.org/2009/03/28/PowerShell20CTP3ModulesInPracticeClosures.aspx

It does this by generating a dynamic module that thunks calls to the interface. The solution is in pure powershell script (no nasty add-type tricks).

-Oisin