I have some troubles with using Portable Class Library. I develop both iOS and Android app and I want to create shared business layer using PCL. However, I use WCF class. Particularly the problem is when I use IExtendableObject, which isn’t exist in PCL. Is it possible to circumvent this problem?
Sorry, but what is exactly IExtendableObject ? Do you mean IExtensibleDataObject ?
Exposing a WCF service does not requires Xamarin. Use your favorite IDE to designa and develop it. You just have to use basicHttpBinding, because Xamarin can only consume a WCF web service using this kind of binding. Do not create a WCF service with a PCL !
PCL allows you to share code between all your mobile applications. In your case, this is at least the proxy code. To create a Xamarin compatible proxy you will use the Silverlight Service Model Proxy Generation Tool from Silverlight SDK 5 (SLsvcUtil.exe). Unfortunatelly, this type ExtensionDataObject isn't available in Silverlight.
I'm a bit surprised to see this requirement in Xamarin as it's used for Forward-Compatible Data Contracts.