Xml validation against xml schema in c # from portable class library

I need to validate XML stored in custom format (not XmlDocument

or XDocument

) in a C # class library.

The class System.Xml.Schema.XmlSchemaValidator

looks like it will conform to the bill since it doesn't rely on a specific format - the calling code inserts data into it. However, I don't believe it is available in the PCL profile, which includes Windows / Windows Universal, Xamarin for iOS and Android.

How can I validate an XML document against an xml schema in this situation?