I have a CustomeAuthorize action filter that forwards the user to signin page if user is not authenticated. I apply this filter to actions or controllers.
[
You can add a judgement by jQuery on the login page.
$(function () { if (window != top) { top.location.href = location.href; } });
OR
edit 'filterContext.Result' in action 'OnActionExecuting'
filterContext.Result = new ContentResult() { Content = "" };