c#解决窗体假死的一种方法

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

        private void button1_Click(object sender, EventArgs e)
        {
            CheckForIllegalCrossThreadCalls = false;
            this.label1.Text = "aaaaa";

            Thread tr = new Thread(testc);
            tr.Start();
        }

        private void testc()
        {
            for (int i = ; i < ; i++)
            {
                Thread.Sleep();
                MessageBox.Show("a");
            }
        }
    }