Formatting Output of Hosted PowerShell

I found a C# example here of invoking a PowerShell script asynchronously from a host application (in folder Chapter 6 - Reading With Events) and am trying to use it in a Windows Forms application.

I have a button (button1) to start the PowerShell script, textBox1 is to enter the script and textBox2 displays the script output. Here is my current code:

using System;
using System.Management.Automation;
using System.Management.Automation.Runspaces;
using System.Windows.Forms;

namespace PSTestApp
{

    delegate void SetTextDelegate(string text);

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            textBox2.Text = "";

            Runspace runspace = 
                RunspaceFactory.CreateRunspace();
            runspace.Open();

            Pipeline pipeline = 
                runspace.CreatePipeline(textBox1.Text);

            pipeline.Output.DataReady += 
                new EventHandler(HandleDataReady);
            pipeline.Error.DataReady += 
                new EventHandler(HandleDataReady);

            pipeline.InvokeAsync();
            pipeline.Input.Close();
        }

        private void HandleDataReady(object sender, EventArgs e)
        {
            PipelineReader<PSObject> output = 
                sender as PipelineReader<PSObject>;

            if (output != null)
            {
                while (output.Count > 0)
                {
                    SetText(output.Read().ToString());
                }
                return;
            }

            PipelineReader<object> error = 
                sender as PipelineReader<object>;

            if (error != null)
            {
                while (error.Count > 0)
                {
                    SetText(error.Read().ToString());
                }
                return;
            }
        }

        private void SetText(string text)
        {
            if (textBox2.InvokeRequired)
            {
                SetTextDelegate d = new SetTextDelegate(SetText);
                this.Invoke(d, new Object[] { text });
            }
            else
            {
                textBox2.Text += (text + Environment.NewLine);
            }
        }
    }
}

The code works, but I have a problem handling the output. Pipeline.Output.Read() returns an instance of PSObject so ToString() returns different things for different objects. For example, if I use this PowerShell command:

Get-ChildItem

the output is:

PSTestApp.exe
PSTestApp.pdb
PSTestApp.vshost.exe
PSTestApp.vshost.exe.manifest

and if I use:

Get-Process

the output is:

...
System.Diagnostics.Process (csrss)
System.Diagnostics.Process (ctfmon)
System.Diagnostics.Process (devenv)
System.Diagnostics.Process (devenv)
...

I could use the returned PSObject instances to construct the output, but it would be nice If I could use the existing PowerShell formatting and get the same output as in the console. When I run the application and check Runspace.RunspaceConfiguration.Formats, the count is 9, and DotNetTypes.format.ps1xml is present, but I don't know how to apply the format.

I have noticed that if I add Out-String at the end of the script:

...
Pipeline pipeline = 
    runspace.CreatePipeline(textBox1.Text);
pipeline.Commands.Add("Out-String");
...

the output is formatted just as in the standard PowerShell console. This works, but if I run a script with a long output that takes some time to execute:

gci d:\ -recurse

Pipeline.Output.DataReady event is raised only once (after the ending Out-String is executed) and only then is the output added to the text box.

Is there a way to use standard PowerShell output formatting in a hosted PowerShell instance?