public partial class Form1 : Form
{
        private delegate void UIOperater(string str);
        Thread thrd;

        public Form1()
        {
            InitializeComponent();            
        }

        private void btnOK_Click(object sender, EventArgs e)
        {
            //打开一个线程  
            if (thrd == null || !thrd.IsAlive)
            {
                thrd = new Thread(new ThreadStart(ChangeBtnTxt));
                thrd.Start();
            }
        }

        private void ChangeBtnTxt()
        {
            uint i = 0;
            while (true)
            {
                i++;
                i = i % 10000;
                this.Invoke(new UIOperater(SetBtnTxt), new object[] { i.ToString() });                
                Thread.Sleep(100);
            }
        }

        private void SetBtnTxt(string str)
        {
            this.btnOK.Text = str;            
        }
}

------解决方案--------------------

好像写错了一点,改过来
C# code

//定义代理ShowStatus
        private delegate void ShowStatus(string str);
        ShowStatus showStatus = new ShowStatus(DoShowStatus);

//用来更新界面元素的函数
        private void DoShowStatus(string txt)
        {
            lock (this)
            {
                //sta_SysStatus是界面控件
                sta_SysStatus.Text = txt;
            }
        }

//调用
        string str = "需要显示的文字";
        this.BeginInvoke(showStatus, str);