跨线程操作无效：控制'progressBar1'从其创建的线程以外的线程访问

Question

我找不到答案：

  

“跨线程操作无效：访问控制'progressBar1'   来自其创建的线程以外的线程。“

这是我的代码：

        private void buttonStart_Click(object sender, EventArgs e)
        {
            ClassCopy cb = new ClassCopy();
            cb.startCopy(textBoxSrc.Text, textBoxDest.Text, true);

            th = new Thread(loading);
            th.Start();

        }

        private loading()
        {
            for (int i = 0; i < 100; i++)
            {
                if (progressBar1.InvokeRequired)
                    progressBar1.Invoke(new Action(loading));
                else
                    progressBar1.Value = i;
            }
        }

Answer 1

这真的只是做

private delegate void EventHandle();

private void loading()
{
    for (int i = 0; i < 100; i++)
    {
        Thread.Sleep(10);
        Invoke(new EventHandle{progressBar1.Value++;})
    }
}

睡眠是这样你会看到变化，否则它会在一毫秒内从0变为100

Answer 2

这个简单的改变将会：

        private void loading()
        {
            for (int i = 0; i < 100; i++)
            {
                if (progressBar1.InvokeRequired)
                    progressBar1.Invoke(new Action(loading));
                else
                    progressBar1.Value = i;
            }
        }