为了更好地演示它，请查看希望在纵向和横向模式下运行的页面。文本USA保持原样，但Hello会响应方向。
似乎只能锁定特定页面的方向，而不能锁定特定视图或元素。
MainActivity.cs:

protected override void OnCreate(Bundle savedInstanceState)
{
    base.OnCreate(savedInstanceState);
    MessagingCenter.Subscribe<MainPage>(this, "Portrait", sender =>
    {
        RequestedOrientation = ScreenOrientation.Portrait;
    });Sensor

    MessagingCenter.Subscribe<MainPage>(this, "Sensor", sender =>
    {
        RequestedOrientation = ScreenOrientation.Sensor;
    });
}

Page.xaml.cs:

protected override void OnAppearing()
{
    base.OnAppearing();
    MessagingCenter.Send(this, "Portrait");
}

protected override void OnDisappearing()
{
    base.OnDisappearing();
    MessagingCenter.Send(this, "Sensor");
}

有关详细信息，您可以查看此案例：Control single page orientation and view rotation in Xamarin Forms .
我也搜索了其他案例，你可以参考：一对一对一，一对一。