Xamarin.Android 禁止横屏 /竖屏
this.RequestedOrientation = Android.Content.PM.ScreenOrientation.Portrait;//竖屏,禁止横屏
this.RequestedOrientation = Android.Content.PM.ScreenOrientation.Nosensor;//横屏,禁止竖屏
https://blog.csdn.net/xionglifei2014/article/details/88892075