异步后如何在主线程上运行代码

Question

I have code that will only run on the main thread, but before that code can run, I need to initialize an object. Is there anyway I can force async code to run sync? The functions after the awaits are API calls, and therefore I cannot modify those directly.

    public partial class MainWindow : Window
    {
        private MustBeInit mbi;

        public MainWindow() {
            InitializeComponent();
            // async code that initializes mbi
            InitMbi(); 
            // mbi must be done at this point
            SomeCodeThatUsesMbi();
        }

        public async void InitMbi() {
            mbi = new MustBeInit();
            await mbi.DoSomethingAsync();
            await mbi.DoSomethingElseAsync();

            // is there any way i can run these two methods as not await and
            // run them synchronous?
        }

        public void SomeCodeThatUsesMbi() {
            DoSomethingWithMbi(mbi); // mbi cannot be null here
        }
    }

Answer 1

You can't use the await in constructors, but you can put the whole thing into an async event handler subscribed to the Loaded event of the Window :

public MainWindow()
{
   this.Loaded += async (s, e) => 
   {
        await InitMbi(); 
        // mbi must be done at this point
        SomeCodeThatUsesMbi();
   };

   InitializeComponent();
}

And don't forget to change the return value of your InitMbi() to Task :

public async Task InitMbi()

Answer 2

 // is there any way i can run these two methods as not await and // run them synchronous? 

Yes, just remove the await before the method call like:

public async void InitMbi() {
    mbi = new MustBeInit();
    mbi.DoSomethingAsync();
    mbi.DoSomethingElseAsync();

    // is there any way i can run these two methods as not await and
    // run them synchronous?
}

But be aware of the fact that this will block your main thread!