好吧，事实证明我不是唯一的https://github.com/xamarin/Xamarin.Forms/issues/11183似乎是列表视图中的错误.降级到 Xamarin.Forms 版本 4.6.0.847 将解决这个问题

well, it turns out i am not the only one https://github.com/xamarin/Xamarin.Forms/issues/11183 seems to be a bug in listview. downgrade to Xamarin.Forms version 4.6.0.847 will solve this problem