How to `WriteVerbose`/`WriteDebug`/... from classes which don't inherit from `Cmdlet`

Question

I'm trying to write a binary module for PowerShell. However I have a problem as I'd like to export common functionality into a helper method:

class Foo {
    Bar DoBaz() {
        if (bazzed) {
            WriteWarning(this.ToString() + " already bazzed");
            return baz;
        }
        // ...
    }
}

This of course doesn't work as WriteVerbose is a method of Cmdlet. I can pass it as lambda but this seems to be very roundabout way of doing it.

Answer 1

You have to pass the Cmdlet (or more commonly PSCmdlet) instance to the helper method. Here's an example

using System.Management.Automation;

[Cmdlet(VerbsDiagnostic.Test, "Cmdlet")]
public class TestCmdletCommand : PSCmdlet
{
    protected override void ProcessRecord()
    {
        HelperMethods.WriteFromHelper(this, "message");
    }
}

public static class HelperMethods
{
    public static void WriteFromHelper(PSCmdlet cmdlet, string message)
    {
        cmdlet.WriteVerbose(message);
    }
}