using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Threading;

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

    private void button1_Click(object sender, EventArgs e)
    {
      MyThread MyInstance = new MyThread();
      label1.Text = "Gestartet";
      while (MyInstance.Thread.IsAlive)
      {
        textBox1.Text = MyInstance.Output;
        Application.DoEvents();
      }
      MyInstance.Thread.Join();
      label1.Text = "Beendet";
      textBox1.Text = MyInstance.Output;
    }
  }
  public class MyThread
  {
    public Thread Thread;
    public string Output;

    public MyThread()
    {
      this.Thread = new Thread(new ThreadStart(Execute));
      this.Thread.Start();
    }
    void Execute()
    {
      for (int i = 1; i <= 5e6; i++)
      {
        Output = i.ToString();
      }
    }
  }
}