UWP C#将UI对象返回到主线程上的同步扩展方法

我正在尝试为

页面

类编写一个扩展方法，该类将返回一个用户控件，该控件是根

网格

动态创建的子控件。我遇到的问题是如何处理

页面

类的

内容

属性

其目的是返回控件以检查控件的属性，并且主要从主线程调用

以下是我想做的：

public static MyUserControl GetControlByTag(this Page page, int tag) {
    //throws "marshalled from a different thread" exception
    Grid rootGrid = page.Content as Grid;  

    if(rootGrid != null) {
        var controls = rootGrid.Children.OfType<MyUserControl>();

        foreach(MyUserControl control in controls)
        {
            if(control.Tag == tag) return control;
        }

    return null;
}

---

我通过MSDN找到了解决方案：

public static MyUserControl GetControlByTag(this Page page, int tag) {
    MyUserControl rtn = null; 

    page.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => {
        Grid rootGrid = page.Content as Grid;

        if(rootGrid != null) {
            var controls = rootGrid.Children.OfType<MyUserControl>();

            foreach(MyUserControl control in controls)
            {
                if(control.Tag == tag) rtn = control;
            }
        }
    }).AsTask().Wait(); //Runs the dispatcher synchronously

    return rtn;
}

public static MyUserControl GetControlByTag(this Page page, int tag) {
    MyUserControl rtn = null; 

    page.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => {
        Grid rootGrid = page.Content as Grid;

        if(rootGrid != null) {
            var controls = rootGrid.Children.OfType<MyUserControl>();

            foreach(MyUserControl control in controls)
            {
                if(control.Tag == tag) rtn = control;
            }
        }
    }).AsTask().Wait(); //Runs the dispatcher synchronously

    return rtn;
}

public static MyUserControl GetControlByTag(this Page page, int tag) {
    Grid rootGrid = page.Content as Grid;

    if(page.Dispatcher.HasThreadAccess) {
        //Code to run
    }
    else {
        page.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => {
            //Code to run
        }).AsTask().Wait();
    }
}