Little sample of Xamarin Forms new preview for Windows Store. You can read the article in spanish: http://geeks.ms/blogs/jyeray/archive/2015/03/22/xamarin-forms-preview-de-xamarin-forms-para-windows-xaml.aspx
English version: http://www.c-sharpcorner.com/UploadFile/761867/xamarin-forms-for-windows-preview-first-steps/