c# - 如何使用 Task.Wait 避免 WinForm 卡住

Question

所以我有类似的代码

private void doSmth()
{
   str = makeStr();
}
private void button_Click(object sender, EventArgs e)
{
   Task task = new Task(doSmth);
   task.Start();
   task.Wait();
   textBox.Text = str;
}

太冷了，我知道为什么会这样，因为 Wait()。我试图像这样使用 ContinueWith()

task.ContinueWith((t) => {textBox.Text = str;});

但是抛出 InvalidOperationException 不起作用:

The calling thread cannot access this object because a different thread owns it

我该如何解决这个问题？也许我应该完全使用另一种方法来实现我想要的。谢谢。

Answer 1

你会想要这个:

private String DoSomething() {

    return makeStr(); // return it, don't set it to a field.
}

private async void button_Click(...) {

    String result = await Task.Run( DoSomething );
    textBox.Text = result;
}

...等价于此:

private async void button_Click(...) {

    // Task<> is the .NET term for the computer-science concept of a "promise": https://en.wikipedia.org/wiki/Futures_and_promises
    Task<String> resultPromise = Task.Run( DoSomething ); 
    String result = await resultPromise;
    textBox.Text = result;
}

...这(大致)等同于此:

private void button_Click(...) {

    Thread thread = new Thread( () => {

        String result = DoSomething();
        this.BeginInvoke( () => {

            this.textBox.Text = result;
        } );

    } );
    thread.Start();
}