using System;
using System.Windows.Forms;
using System.Threading;

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

        /* デザイナ側のDisposeに追加
        protected override void Dispose(bool disposing)
        {
            if (disposing && th != null)
            {
                th.Interrupt();
                th.Join();
            }
            ...
        }
        */

        Thread th;
        private void button1_Click(object sender, EventArgs e)
        {
            if (th == null)
            {
                th = new Thread(() =>
                {
                    try
                    {
                        String s;
                        this.Invoke((MethodInvoker)(() => s = textBox1.Text));
                        int st = 0;
                        int.TryParse(textBox1.Text, out st);
                        for (int i = st; ; i++)
                        {
                            this.Invoke((MethodInvoker)(() => { textBox1.Text = "" + i; }));
                            //this.BeginInvoke((MethodInvoker)(() => { textBox1.Text = "" + i; }));
                        }
                    }
                    catch (ThreadInterruptedException) { }
                });
                th.Start();
                button1.Text = "停止";
            }
            else
            {
                th.Interrupt();
                th.Join();
                th = null;
                button1.Text = "開始";
            }
        }
    }
}