Using Powershell into C# to find out installed windows Features on WindowsServer2012

I am trying to fetch the Installed Windows Features using powershell in C# code.But unable to get them.The code I am writing is:

private void button1_Click(object sender, EventArgs e) { Runspace run = RunspaceFactory.CreateRunspace(); run.Open();

        PowerShell power = PowerShell.Create();
        power.Runspace = run;

       power.AddScript(" $d = get-date; $s = 'Hi How are you ?'; $name='mukul'; $get=(Get-WindowsFeature -name File-Services).Installed; " +
              "$d; $s; $name; $get");
        foreach (PSObject result in power.Invoke())
        {

            MessageBox.Show(result.BaseObject.ToString() + "\n");


        }


    }

Till $name it is working fine but giving null reference exception at $get.Please help.