How do I call overloaded static methods from the .net framework in Powershell?

Question

Below is a transcript of what I've tried and what happens.

I'm looking for how to call a specific overload along with an explanation of why the following does not work. If your answer is "you should use this commandlet instead" or "call it twice" please understand when I don't accept your answer.

PS C:\> [System.IO.Path]::Combine("C:\", "foo")
C:\foo
PS C:\> [System.IO.Path]::Combine("C:\", "foo", "bar")
Cannot find an overload for "Combine" and the argument count: "3".
At line:1 char:26
+ [System.IO.Path]::Combine <<<< ("C:\", "foo", "bar")
    + CategoryInfo          : NotSpecified: (:) [], MethodException
    + FullyQualifiedErrorId : MethodCountCouldNotFindBest

PS C:\> [System.IO.Path]::Combine(, "C:\", "foo", "bar")
Missing ')' in method call.
At line:1 char:27
+ [System.IO.Path]::Combine( <<<< , "C:\", "foo", "bar")
    + CategoryInfo          : ParserError: (CloseParenToken:TokenId) [], Paren
   tContainsErrorRecordException
    + FullyQualifiedErrorId : MissingEndParenthesisInMethodCall

PS C:\> [System.IO.Path]::Combine($("C:\", "foo", "bar"))
Cannot find an overload for "Combine" and the argument count: "1".
At line:1 char:26
+ [System.IO.Path]::Combine <<<< ($("C:\", "foo", "bar"))
    + CategoryInfo          : NotSpecified: (:) [], MethodException
    + FullyQualifiedErrorId : MethodCountCouldNotFindBest

this is what I do in c#, which works:

var foobar = Path.Combine(@"C:\", "foo", "bar");
Console.WriteLine(foobar);

What Powershell will invoke that specific overload? Path.Combine has both of these:

public static string Combine (string path1, string path2, string path3);
public static string Combine (params string[] paths);

Is it possible to call both of these, or just one? Obviously, in this specific case, it's difficult to tell the difference.

Answer 1

The Path overloads that accept multiple arguments like that are only available in .NET 4 and up. You need to create a config file to tell Powershell to launch using .NET 4, which will give you access to those methods.

Create a file called "powershell.exe.config" in $pshome with the following contents:

<?xml version="1.0"?> 
<configuration> 
    <startup useLegacyV2RuntimeActivationPolicy="true"> 
        <supportedRuntime version="v4.0.30319"/> 
        <supportedRuntime version="v2.0.50727"/> 
    </startup> 
</configuration>