Authorize Attribute with Multiple Roles

Try to create custom authorize attribute like this.

public class AuthorizeRolesAttribute : AuthorizeAttribute
{
    public AuthorizeRolesAttribute(params string[] roles) : base()
    {
        Roles = string.Join(",", roles);
    }
}

Assuming your roles will be the same for multiple controllers, create a helper class:

public static class Role
{
    public const string Administrator = "Administrator";
    public const string Assistant = "Assistant";
}

Then use it like so:

public class MyController : Controller
{
    [AuthorizeRoles(Role.Administrator, Role.Assistant)]
    public ActionResult AdminOrAssistant()
    {                       
        return View();
    }
}