c# - Hosted PowerShell cannot see Cmdlets in the same Assembly

Question

I'm trying to run PowerShell scripts from my C# code, that will use custom Cmdlets from the assembly that runs them. Here is the code:

using System;
using System.Management.Automation;

[Cmdlet(VerbsCommon.Get,"Hello")]
public class GetHelloCommand:Cmdlet
{
    protected override void EndProcessing()
    {
        WriteObject("Hello",true);
    }
}

class MainClass
{
    public static void Main(string[] args)
    {
        PowerShell powerShell=PowerShell.Create();
        powerShell.AddCommand("Get-Hello");
        foreach(string str in powerShell.AddCommand("Out-String").Invoke<string>())
            Console.WriteLine(str);
    }
}

When I try to run it, I get a CommandNotFoundException. Did I write my Cmdlet wrong? Is there something I need to do to register my Cmdlet in PowerShell or in the Runspace or something?

Answer 1

The easiest way to do this with your current code snippet is like this:

using System; 
using System.Management.Automation; 

[Cmdlet(VerbsCommon.Get,"Hello")] 
public class GetHelloCommand:Cmdlet 
{ 
    protected override void EndProcessing() 
    { 
        WriteObject("Hello",true); 
    } 
} 

class MainClass 
{ 
    public static void Main(string[] args) 
    { 
        PowerShell powerShell=PowerShell.Create();

        // import commands from the current executing assembly
        powershell.AddCommand("Import-Module")
            .AddParameter("Assembly",
                  System.Reflection.Assembly.GetExecutingAssembly())
        powershell.Invoke()
        powershell.Commands.Clear()

        powershell.AddCommand("Get-Hello"); 
        foreach(string str in powerShell.AddCommand("Out-String").Invoke<string>()) 
            Console.WriteLine(str); 
    } 
} 

This assumes PowerShell v2.0 (you can check in your console with $psversiontable or by the copyright date which should be 2009.) If you're on win7, you are on v2.