c# - Design View Model as internal class -

i'm working on windows runtime component project must expose few controls outside world. use design view models have like:

public sealed class firstpaneldesignviewmodel { ... } 

it works supposed during design time class exposed outside world of project, thing not desirable. can modify this:

internal class firstpaneldesignviewmodel { ... } 

but designer (.xaml file opened) complains cannot access class , render not occur anymore:

the name "firstpaneldesignviewmodel" not exist in namespace "using:someproject.designviewmodels".

is there way use design view models in windows runtime component without exposing outside?

i guess use friend assemlies

using system.runtime.compilerservices; using system;  [assembly: internalsvisibleto("assemblyb")]  // class internal default. class friendclass {     public void test()     {         console.writeline("sample class");     } }  // public class has internal method. public class classwithfriendmethod {     internal void test()     {         console.writeline("sample method");     }  }