Invoking PowerShell, with variables

PowerShell invoker.cs

using System;
using System.IO;
using System.IO.IsolatedStorage;
using System.Management.Automation;
using System.Text;
using PowerShellHosting.Util;

namespace PowerShellHosting.File
{
    public class FileBasedPowerShellRunner : IPowerShell
    {
        public PowerShellExecutionResult Execute(PowerShellArguments arguments)
        {
            const string powerShellExe = @"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe";

            var bootstrapFile = Path.Combine(arguments.WorkingDirectory, "Bootstrap." + Guid.NewGuid().ToString() + ".ps1");

            using (var writer = new StreamWriter(bootstrapFile))
            { 
                writer.WriteLine("## Variables:");
                foreach (var variable in arguments.Variables)
                {
                    writer.WriteLine("$" + variable.Key + " = [System.Text.Encoding]::Unicode.GetString( [Convert]::FromBase64String( \"" + Convert.ToBase64String(Encoding.Unicode.GetBytes(variable.Value)) + "\" ) )");
                }

                writer.WriteLine();
                writer.WriteLine("## Invoke:");

                writer.WriteLine(". .\\Deploy.ps1");
                writer.Flush();
            }

            try
            {
                var commandArguments = new StringBuilder();
                commandArguments.Append("-NonInteractive ");
                commandArguments.Append("-NoLogo ");
                commandArguments.Append("-ExecutionPolicy Unrestricted ");
                commandArguments.AppendFormat("-File \"{0}\"", bootstrapFile);

                var exit = SilentProcessRunner.ExecuteCommand(powerShellExe, commandArguments.ToString(), Environment.CurrentDirectory,
                    output => arguments.OutputStream.OnWritten(output),
                    error => arguments.OutputStream.OnWritten("ERROR: " + error));

                return new PowerShellExecutionResult(exit, null);
            }
            finally
            {
                System.IO.File.Delete(bootstrapFile);
            }
        }
    }
}