Adds a CSS class to the element if the it has an attribute of the specified type or if the model member is a non-nullable value type.
Inheritance: ThreadSafeMemberBehavior
 protected void Establish_context(Expression<Func<FakeModel, object>> member)
 {
     behavior = new RequiredCssClassBehavior<RequiredAttribute>();
     element = new TextBox(member.GetNameFor(), member.GetMemberExpression(), null);
 }
 protected void Establish_context(Expression<Func<FakeModel, object>> member, string requiredClass)
 {
     behavior = requiredClass == null ? new RequiredCssClassBehavior() : new RequiredCssClassBehavior(requiredClass);
     element = new TextBox(member.GetNameFor(), member.GetMemberExpression(), null);
 }