How do I conditionally add a class with Add-Type -TypeDefinition if it isn't added already?

Question

Consider the following PowerShell snippet:

$csharpString = @\"
using System;

public sealed class MyClass
{
    public MyClass() { }
    public override stri         


        

Answer 1

There's a nicer way to do this without incurring the cost of exceptions:

if (-not ("MyClass" -as [type])) {
    add-type @"
        public class MyClass { }
"@
}

update: well, apparently powershell signals internally with an exception anyway. It has a bad habit of doing this. The interpreter uses SEH to signal with the break and continue keywords, for example.