Is this meant to be an ASP.Net web-form application or a C# windows-form application?
If it's a web-form application then:
1)It should have been posted in the ASP.Net forum
2) I'm not really sure how to get the value of the address bar if it's an URL outside of your site (such as google) but you can get the query string of the URL leading to your ASP.Net page (ie: www.yoursite.com?query=value by using
string myQuery = ClientQueryString;
If you're using a webBrowser control in a windows-forms application you can use the following to get the current URL from the webBrowser component but it'd be somewhat pointless since using a webBrowser component, the navigation would be based off another text input component of your windows form and you could simply get the info from there:
Don't know if either of those help, the question wasn't exceedingly clear to me sorry :( Please remember to mark the thread as solved if it does get resolved though.