您如何从UI线程调用方法？

Question

我正在尝试从多线程程序访问Microsoft Store。该程序本身运行良好-那里没有问题，但是方法

Windows.Foundation.IAsyncOperation<StorePurchaseResult> purchase = product.RequestPurchaseAsync();

引发异常：

“无效的窗口句柄。\ r \ n \ r \ n必须从UI调用此函数线程“

我的代码如下...

        private void testButton_Click(object sender, EventArgs e)
        {
            //Dispatcher dispUI = Dispatcher.CurrentDispatcher;
            //dispUI.BeginInvoke((ThreadStart)delegate ()
            //{
            //    _ = SetStore();
            //});

            //Dispatcher.BeginInvoke(new Action(TestStuff));


            _ = SetStore();

        }

        [ComImport]
        [Guid("4AEEEC08-7C92-4456-A0D6-1B675C7AC005")]
        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
        private interface IInitializeWithWindow
        {
            void Initialize(IntPtr hwnd);
        }


        private async Task SetStore()
        {
            try
            {
                StoreContext theStore = StoreContext.GetDefault();

                // "Unable to cast object of type 'Windows.Services.Store.StoreContext' to type 'IInitializeWithWindow'."
                // IInitializeWithWindow initWindow = (IInitializeWithWindow)(object)theStore;
                // initWindow.Initialize(System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle);

                StoreProductResult app = await theStore.GetStoreProductForCurrentAppAsync();

                // This works...
                StoreProduct product = app.Product;
                string title = product.Title;
                string price = product.Price.FormattedPrice;

                // This works...
                StoreAppLicense license = await theStore.GetAppLicenseAsync();
                bool trial = license.IsTrial;
                bool full = license.IsActive;

                // "Invalid window handle.\r\n\r\nThis function must be called from a UI thread" 
                StorePurchaseResult result = await theStore.RequestPurchaseAsync("9NRFBVGVGW8K");


                // "Invalid window handle.\r\n\r\nThis function must be called from a UI thread" 
                // Windows.Foundation.IAsyncOperation<StorePurchaseResult> purchase = product.RequestPurchaseAsync();
            }
            catch (Exception e)
            {
                int a = 1;
            }

        }

我已将VS2019 UWP安装程序项目与商店相关联，我认为这就是为什么其他方法无需使用IInitializeWithWindow强制转换商店对象即可返回正确答案的原因（这也会引发错误，但绕过似乎使代码工作）。

我想我必须以某种方式进入UI线程-不知道如何。来自各地的各种示例似乎对我不起作用。谁能帮我吗？

Answer 1

对于UWP，您需要使用以下代码来调用UI线程：

await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () => {
    //UI code here
});