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

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Thread th = new Thread(YourThread);
            th.Start();
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            )
            {
                detailCollectedEvent.Set();                      // 当textBox1的文本超过4位，发一个通知
            }
        }

        AutoResetEvent detailCollectedEvent = new AutoResetEvent(false);
        void YourThread()
        {
            MessageBox.Show("input you bank account details into the textbox");
            detailCollectedEvent.WaitOne();                      // 等候通知
            MessageBox.Show("we will keep the secret.");
        }
    }
}

public partial class Form1 : Form
   {
       public Form1()
       {
           InitializeComponent();
       }
       private delegate void setText(string msg);
       private setText settext;

       private void button1_Click(object sender, EventArgs e)
       {
           Thread objThread = new Thread(new ThreadStart(delegate
           {
               YourThread();
           }));
           objThread.Start();

           settext = new setText(setTextbox);
       }

       private void textBox1_TextChanged(object sender, EventArgs e)
       {
           )
           {
               detailCollectedEvent.Set();                      // 当textBox1的文本超过4位，发一个通知
           }
       }
       public void setTextbox(string msg)
       {
           textBox1.Text = msg;
       }
       AutoResetEvent detailCollectedEvent = new AutoResetEvent(false);
       void YourThread()
       {
           ; i < ; i++)
           {
               this.BeginInvoke(settext, "开始");
               detailCollectedEvent.WaitOne();                      // 等候通知
               this.BeginInvoke(settext, "输入正确" + i.ToString());
           }
       }

   }