Runs PowerShell from C# through System.Management.Automation

PowershellRunspace.cs

using System;
using System.Management.Automation;
using System.Collections.ObjectModel;

static void Main(string[] args)
        {

        //Using this class: https://docs.microsoft.com/en-us/dotnet/api/system.management.automation.powershell?view=powershellsdk-1.1.0
        using (PowerShell PowerShellInstance = PowerShell.Create())
                    {
                        PowerShellInstance.AddScript("line 1");

                        PowerShellInstance.AddScript("line 12");

                        PowerShellInstance.AddScript("line n");
                        
                        //Run command provided by user
                        PowerShellInstance.AddScript(args[0]);

                        //Used
                        Collection <PSObject> PSOutput;

                        // invoke execution on the pipeline (collecting output)
                        PSOutput = PowerShellInstance.Invoke();

                        // loop through each output object item
                        foreach (PSObject outputItem in PSOutput)
                        {
                            // if null object was dumped to the pipeline during the script then a null
                            // object may be present here. check for null to prevent potential NRE.
                            if (outputItem != null)
                            {
                                //TODO: do something with the output item 
                                // outputItem.BaseOBject
                                Console.WriteLine(outputItem);
                            }
                        }

                    }
}