Control.CheckForIllegalCrossThreadCalls = false不可在多线程中使用

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

//导入多线程的命名空间
using System.Threading;

namespace WindowsFormsApplication16
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        public void MehtodOne()
        {
            for (int i = 0; i < 300; i++)
            {
                this.textBox1.Text += "************";
            }
        }

        public void MethodTwo()
        {
            for (int i = 0; i < 300; i++)
            {
                this.textBox2.Text += "xxxxxxxxxxxxxxxxx";
            }
        
        }

        //public delegate void ThreadStart();
        private void button1_Click(object sender, EventArgs e)
        {

            #region  "ThreadStart" 表示方法,在系统线程的线程执行 public delegate void ThreadStart();
            // 摘要:
             // Represents the method that executes on a System.Threading.Thread.
            //表示方法,在系统线程的线程执行
            //[ComVisible(true)]
            //public delegate void ThreadStart();
            #endregion

            ThreadStart firstStart = this.MehtodOne;//调用  public void MehtodOne()

            #region "  Thread firstThread = new Thread(firstStart);"这句类似以下委托方法
            //public class TestThread
            //    {
            //        ThreadStart s;

            //        public TestThread(ThreadStart start)
            //        {
            //            s = start;
            //        }

            //        public void Start()
            //        {
            //            s();
            //        }

            //  }

            #endregion

            Thread firstThread = new Thread(firstStart);
            firstThread.Start();

            //TestThread firstThread1 = new TestThread(firstStart);
            //firstThread1.Start();

            ThreadStart secondStart = this.MethodTwo; //调用  public void MethodTwo()
            Thread secondThread = new Thread(secondStart);
            secondThread.Start();
          
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Control.CheckForIllegalCrossThreadCalls = false;//这个意思是不可在多线程中使用
        }

   
    }
}