How to get a Powershell script to launch from Visual Studio

Depending on your goals there's another way to go about this.

A mini-class with a PS wrapper :)

Add-Type -TypeDefinition @"
using System.Management.Automation;
using System.Management.Automation.Runspaces;

public class PS
{
    PowerShell host = PowerShell.Create(InitialSessionState.CreateDefault());

    public object RunScript(string path)
    {
        return host.AddScript(path).Invoke();
    }
}
"@ -ReferencedAssemblies ([PowerShell].Assembly.Location)

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Once it's created, the method can be invoked after you instantiate the class.

[PS]::new().RunScript('C:\Development\scratch\test.ps1')

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The advantage of this approach is that you can get detailed error information. Runtime errors (terminating errors) will throw as exceptions when Invoke is called. Non-terminating errors are written to host.Streams.Error.

I just noticed the VB .NET tag. Is the C# example easy enough for you to translate? I can change it, but I always have to double check VB .NET syntax which is only worthwhile if you find it to be.

Process.Start("powershell", "-noexit  -ExecutionPolicy Bypass -file 'c:\Temp\myScript.ps1'")

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Yes, you can. The Error collection contains a list of ErrorRecord objects. This example should push that to the console, it shows how I would distinguish between the different types of error (runtime vs managed).

Add-Type -TypeDefinition @"
Imports System
Imports System.Management.Automation
Imports System.Management.Automation.Runspaces

Public Class PS
    Dim host As PowerShell = PowerShell.Create(InitialSessionState.CreateDefault())

    Public Function RunScript(path As String) As object
        Try
            Dim value As Object = host.AddScript(path).Invoke()
            If host.HadErrors Then
                For Each errorRecord as ErrorRecord in host.Streams.Error
                    Console.WriteLine(errorRecord.Exception.Message)
                Next
            Else
                Return value
            End If
        Catch e As Exception
            Console.WriteLine(e.Message)
        End Try

        Return Nothing
    End Function
End Class
"@ -ReferencedAssemblies ([PowerShell].Assembly.Location) -Language VisualBasic

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It's a static method on the System.Management.Automation.PowerShell class. Be a touch careful about assembly versions though, Visual Studio is terrible at picking a modern version when selecting references. I normally feed it the path revealed by the snippet below when adding the reference:

[PowerShell].Assembly.Location

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That gets it the assembly associated with PowerShell 5.1 not PowerShell 2.0.

Have a look at this web page. Calling a PowerShell Script From Your .NET Code.

Hmm okay, well at least that bit is right.

The CreateNestedPowerShell method is a method on the instantiated host, we don't need that one. To create the host in the first place you want the static method on the PowerShell type.

Where this:

PowerShell.Create(InitialSessionState.CreateDefault())

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Is this static method:

https://msdn.microsoft.com/en-us/library/hh470726(v=vs.85).aspx?cs-save-lang=1&cs-lang=vb#code-snippet-1

This is my assemblies full name:

System.Management.Automation, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35

I think you have the right assembly.

Going back to this:

> The "Host" object that we're instantiating has no "Create" method attached to it

The create method is not on the instantiated "Host" object. It's a static method on the PowerShell type (does not require an instantiated object).

You're right that the instantiated "Host" object does not have such a method. But if you've instantiated it, you're done with that part and it's on to loading a script into the Commands collection (using the AddScript method).

Yay :) Good work :)