Implement a PowerShell pipeline with a script parameter in C#

How are running the script?

Have you tries using ProcessStart
http://www.dotnetperls.com/process
https://msdn.microsoft.com/en-us/library/system.diagnostics.process.start(v=vs.110).aspx

Another option would be to use the Powershell class
https://msdn.microsoft.com/en-us/library/system.management.automation.powershell(v=vs.85).aspx
http://blogs.msdn.com/b/kebab/archive/2014/04/28/executing-powershell-scripts-from-c.aspx

Michael, thanks for you input :) I am using the code below (I have only included the relevant snippet):

//After we have done this, we can now do the remote calls that will be executed on the server side as script blocks.
powershell = PowerShell.Create();
command = new PSCommand();
command.AddScript("Invoke-Command -ScriptBlock { Get-Mailbox -ResultSize Unlimited } -Session $ra");
//command.AddScript("Invoke-Command -ScriptBlock { Get-Mailbox -ResultSize Unlimited |Select-Object DisplayName,Alias,Database,ServerName,PrimarySmtpAddress, @{Name=\"EmailAddresses\";Expression={$_.EmailAddresses |Where-Object {$_.PrefixString -ceq \"smtp\"} | ForEach-Object {$_.SmtpAddress}}} } -Session $ra");
powershell.Commands = command;
powershell.Runspace = myRunSpace;

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What's interesting is that the call to command.AddScript("Invoke-Command -ScriptBlock { Get-Mailbox -ResultSize Unlimited } -Session $ra"); works and I get results. It's just when I try to execute the more complex PowerShell script which get more refined data back that I get the issues. the EmailAddress column returned by this working version includes multiple SMTP address alternatives and other detail which I do not need. The more complex PowerShell script strips out these other details. The complex PowerShell script works when I run it from PowerShell ISE. I only get issues when I run it from C#, but I am not sure how one constructs that pipeline from C#.