The name of an optional View class to instantiate and use as an action view. See Android.Views.IMenuItem.SetActionView(Android.Views.View) for more info.

Must be a string value, using '\\;' to escape characters such as '\\n' or '\\uxxxx' for a unicode character.

This may also be a reference to a resource (in the form "@[package:]type:name") or theme attribute (in the form "?[package:][type:]name") containing a value of this type.

[Android Documentation]