C#

using System;
using System.Threading;
using System.IO;

namespace Threaded
{
	public class ThreadingTextWriter
	{
		private string path = "";
		private string textToWrite = DateTime.Now.ToString();
		
		public string Path
		{
			get
			{
				return this.path;
			}
			set
			{
				this.path = value;
			}
		}
		public string TextToWrite
		{
			get
			{
				return this.textToWrite;
			}
			set
			{
				this.textToWrite = value;
			}
		}
		
		public void Write()
		{
			Thread.Sleep(1000);
			File.WriteAllText(path, this.textToWrite);
		}
		
		public ThreadingTextWriter(string path, string textToWrite)
		{
			this.path = path;
			this.textToWrite = textToWrite;
		}
	}
	
	public static class Program
	{
		public static void Main(string[] args)
		{
			ThreadingTextWriter ttw1 = new ThreadingTextWriter(@"output1.txt", @"Output from ThreadingTextWriter1");
			ThreadingTextWriter ttw2 = new ThreadingTextWriter(@"output2.txt", @"Output from ThreadingTextWriter2");
			
			// Create new thread
			Thread ttw2Thread = new Thread(new ThreadStart(ttw2.Write));
			
			// Start write from 2
			ttw2Thread.Start();
			
			// Write from 1
			ttw1.Write();
			
			// Wait to make sure that all threads have finished writing.
			Thread.Sleep(1000);
			
			Console.WriteLine(@"Completed write tests");
		}
	}
}

• I havn't locked the files so other processes may try and access them. To solve this you can use the FileStream constructor as you have done, this I think has an option for locking the file for read/write access, I just can't remember off the top of my head
• This uses .NET 2.0 (hence the File.WriteAllText) so this will need to be changed to suit you needs

Authorof22 wrote:

so I can tag the items

public struct Car
{
    private string name;
    public string Name
    {
        get
        {
            return this.name;
        }
    }
    private string license;
    public string License
    {
        get
        {
            return this.license;
        }
    }

    public override string ToString()
    {
        return this.License;
    }

    public Car(string name, string license)
    {
        this.name = name;
        this.license = license;
    }
}

TreeView.SelectedNode.Index