C# 如何将按钮添加到UIDocumentInteractionController预览

C# 如何将按钮添加到UIDocumentInteractionController预览,c#,xamarin.ios,uidocumentinteraction,uidocument,C#,Xamarin.ios,Uidocumentinteraction,Uidocument,我正在使用UIDocumentInteractionController进行文件预览: interactionController = UIDocumentInteractionController.FromUrl(url); interactionController.Delegate = new UIDocumentInteractionControllerDelegateClass(this); InvokeOnMainThread(delegate{interaction

我正在使用
UIDocumentInteractionController
进行文件预览:

interactionController = UIDocumentInteractionController.FromUrl(url);    
interactionController.Delegate = new UIDocumentInteractionControllerDelegateClass(this);    
InvokeOnMainThread(delegate{interactionController.PresentPreview(true);}
});
如何在视图顶部添加自定义按钮以执行某些操作