很遗憾，这无法与MonoTouch一起使用-但是我们已针对下一个测试版（5.3.3）进行了修复，

This has unfortunately been impossible to do with MonoTouch - but we've fixed it for the next beta (5.3.3) which will hopefully be released soon.

5.3.3发布后，您可以使用以下示例： https://github.com/xamarin/monotouch-samples/tree/monotouch-5.4/CustomPropertyAnimation ，了解如何操作。

Once 5.3.3 has been released you can use this sample: https://github.com/xamarin/monotouch-samples/tree/monotouch-5.4/CustomPropertyAnimation to see how to do it.