LinqPad demo of how to call PowerShell from C#, passing in parameters and receiving a hashtable response

CallPowerShell.linq

<Query Kind="Statements">
  <GACReference>System.Management.Automation, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35</GACReference>
  <Namespace>System.Management.Automation</Namespace>
</Query>

// create a powershell session
PowerShell ps = PowerShell.Create();

// add a script to emit a PowerShell hashtable which includes a parameter value
ps.AddScript("param($target); Write-Output @{hello = $target}");
ps.AddParameter("target", "World");

// call the script
System.Collections.ObjectModel.Collection<PSObject> results = ps.Invoke();

// take the first emitted result as a dynamic and dump it
dynamic result = results[0];
((string)result.hello).Dump("Should be 'World'");

// tidy up after
ps.Dispose();