为什么我的UIButton委托必须在视图中显示更改之前完全执行？

Question

I'm doing some MonoTouch development, and I really can't figure out an problem I've run into

I'm having an ViewController containing a UIButton. I have added a delegate to the TouchDown event of this button. In this delegate I'm calling a WebService and trying to change the colour and title of the button. However nothing happens to the button before the entire delegate have been executed. The thing is that the webservice is rather slow, so I want to give the users a waiting message by changing the colour and title of the button.

The code:

    public override void ViewDidLoad ()
    {

        View.BackgroundColor = UIColor.Black;

        bookButton = new UIButton( new RectangleF(10,100,this.View.Frame.Width-10 ,40) );

        bookButton.BackgroundColor = UIColor.Clear;
        setButton();

        bookButton.TouchDown += delegate {

            gymClass.book();
            setButton();
            tableView.ReloadData();
            NavigationController.PopViewControllerAnimated( true );

        };

        this.View.AddSubview( bookButton );

    }

Anyone, please?

Answer 1

委托在负责渲染的主线程上执行，因此您将阻止渲染器，直到您返回。