is it possible to understand at Code behind whether page is being called inside iframe or not

Question

I need to understand that whether page is being called inside iframe or not at code behind. Is this possible?

I need to determine it in master page code behind.

asp.net 4.0, C#

Answer 1

In general, no.

Of course you can emit client script that detects iframe and reloads the page with e.g. a querystring.