为什么Thread.Sleep()会冻结表单？

Question

我试着尝试一下Thread.Sleep().我用一个按钮创建了基本的Windows窗体应用程序.

    private void button1_Click(object sender, EventArgs e)
    {
        Thread thread1 = new Thread(DoStuff);
        thread1.Start();

        for (int i = 0; i < 100000; i++)
        {
            Thread.Sleep(500);
            button1.Text +=".";
        }
    }

    public void DoStuff()
    {
       //DoStuff         
    }

当我单击我的按钮时,该DoStuff方法工作正常,但GUI冻结,没有任何反应.有人能解释一下为什么吗？

Answer 1

Thread.Sleep只是睡眠当前线程(即阻止它做任何事情,例如重绘,处理点击等),在你的情况下是UI线程.如果你把它Sleep放在DoStuff你不会遇到块,因为你将在一个单独的线程,虽然你将无法更新button1.根据您使用的.NET版本考虑使用任务并行库,如下所示:

private TaskScheduler _uiScheduler;
public Form1()
{
    InitializeComponent();
    _uiScheduler = TaskScheduler.FromCurrentSynchronizationContext();
}

private void button1_Click(object sender, EventArgs e)
{

    Thread thread1 = new Thread(DoStuff);
    thread1.Start();

    // Create a task on a new thread.
    Task.Factory.StartNew(() =>
        {
            for (int i = 0; i < 100000; i++)
            {
                Thread.Sleep(500);

                // Create a new task on the UI thread to update the button
                Task.Factory.StartNew(() =>
                    { button1.Text += "."; }, CancellationToken.None, TaskCreationOptions.None, _uiScheduler);
            }
        });
}