Screen-scraping a site with a asp.net form login in C#?

I've created a web application in asp.net so far. where i've tried to get some data(site scraping) from secure pag开发者_StackOverflow社区e of a web site.I've used the HttpWebRequest class for this functionality but i haven't accessed the secure page yet. Every time the login pages was scraped not secure page.I have the site user id and password and don't know that which language site has been developed in.

Please advice what should i do ?

Look at the login form. You should be able to POST data to the target of that form, supplying the correct variables for username and password. You should then receive the initial logged in page back.