Call and receive URL data in asp.net

In asp.net (or vb) I must to call a page that only autenticates a user, returning the user data if the logon succed. This way, I would like to implement the sequence:

1. A blank page (mine) re开发者_运维知识库quest the autenticator page (3rd part) automatically on load;
2. The user logs in the autenticator page;
3. My page reads the autenticator page results and do the actions.

I'm a very begginer in asp.net, and I'm using vb.net in the environment for coding the page "onload" event. I'm trying to use the "redirect('url')" method to call the autenticator's page, but in this way, obviously, I can't receive the result. How can I implement this sequence?

Problem solved. I discovered that when I call the autenticator server I must to inform a parameter with the URL for autenticator's page redirecting to (my page, in this case). This way, the autenticator's page itself will request my page after user login, then I'll be able to get the URL parameters with the user data. Thanks.