找了很多C#執行緒更新UI的方法，還是這個最好用。

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

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        SynchronizationContext cuverContext;
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            new Thread(new ThreadStart(ThreadFun)).Start();
        }
        public void ThreadFun()
        {
            while (true)
            {
                cuverContext.Post(new SendOrPostCallback(ThreadSend), null);//第二個引數可以用來傳輸資料
                Thread.Sleep(500);
            }
        }
        public void ThreadSend(Object obj)
        {
            textBox1.Text += textBox2.Text;
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            cuverContext = SynchronizationContext.Current;
        }
    }
}