This program demonstrates how to create a Button in code and process events from it. By default, the Button occupies the entire page.
The ButtonXaml sample is functionally identical but demonstrates how to create a button in XAML.
If you open the solution in Xamarin Studio, it will not be able to load the Windows Phone project; and if you open the solution in Xamarin Studio under Windows, it will not be able to load the iOS project either.
Charles Petzold