Generate classes from XSD file in Xamarin Forms

Hi,

How do I create classes from an XSD file for use in Xamarin forms?

I tried to use Visual Studio and xsd.exe but the code generated uses [System.SerializableAttribute()] which causes an errors:
The type or namespace name 'SerializableAttribute' does not exist in the namespace 'System' (are you missing an assembly reference?)
The type or namespace name 'SerializableAttributeAttribute' does not exist in the namespace 'System' (are you missing an assembly reference?)

I can't continue with anything until I get this resolve so any help is greatly appreciated - Do I need to generate the classes in a different way for use in Xamarin, is there a work around for the error?

Thanks,
Rick.