How to pass a parameter from C# to a PowerShell script file?

Question

From the command line I can do.

.\test.ps1 1

How do I pass the parameter when doing this from C#? I've tried

   .AddArgument(1)
   .AddParameter("p", 1)

And I have tried passing values in as IEnumerable<object> in the .Invoke() but $p does not get the value.

namespace ConsoleApplication1
{
    using System;
    using System.Linq;
    using System.Management.Automation;

    class Program
    {
        static void Main()
        {
            // Contents of ps1 file
            //  param($p)
            //  "Hello World ${p}"

            var script = @".\test.ps1";

            PowerShell
                .Create()
                .AddScript(script)
                .Invoke().ToList()
                .ForEach(Console.WriteLine);
        }
    }
}

Answer 1

How's this?

static void Main()
{
    string script = @"C:\test.ps1 -arg 'hello world!'";
    StringBuilder sb = new StringBuilder();

    PowerShell psExec = PowerShell.Create();
    psExec.AddScript(script);
    psExec.AddCommand("out-string");

    Collection<PSObject> results;
    Collection<ErrorRecord> errors;
    results = psExec.Invoke();
    errors = psExec.Streams.Error.ReadAll();

    if (errors.Count > 0)
    {
        foreach (ErrorRecord error in errors)
        {
            sb.AppendLine(error.ToString());
        }
    }
    else
    {
        foreach (PSObject result in results)
        {
            sb.AppendLine(result.ToString());
        }
    }

    Console.WriteLine(sb.ToString());
}

Here's a similar version that passes an instance of a DateTime

static void Main()
{
    StringBuilder sb = new StringBuilder();

    PowerShell psExec = PowerShell.Create();
    psExec.AddCommand(@"C:\Users\d92495j\Desktop\test.ps1");
    psExec.AddArgument(DateTime.Now);

    Collection<PSObject> results;
    Collection<ErrorRecord> errors;
    results = psExec.Invoke();
    errors = psExec.Streams.Error.ReadAll();

    if (errors.Count > 0)
    {
        foreach (ErrorRecord error in errors)
        {
            sb.AppendLine(error.ToString());
        }
    }
    else
    {
        foreach (PSObject result in results)
        {
            sb.AppendLine(result.ToString());
        }
    }

    Console.WriteLine(sb.ToString());
}

Answer 2

So, to make a long answer short: Use AddCommand instead of AddScript