using multiple Proxy

I am creating threaded website scraper that us开发者_如何学运维es watin .It will search google for my entered string in text box , i want that each thread uses different proxy and they run at same time.is it possible to use proxies without changing registry.i have done with registry and works prefect or any sugesstion

If you use WebRequest, there is a proxy property: http://msdn.microsoft.com/en-us/library/system.net.webrequest.proxy.aspx