Context

Get current AppDomain

AppDomain.CurrentDomain

Get current HttpContext

HttpContext.Current

Get current web request

HttpContext.Current.Request

Get website virtual path

HttpContext.Current.Request.ApplicationPath
Or
HttpRuntime.AppDomainAppVirtualPath

Get website physical path

HttpRuntime.AppDomainAppPath
Or
HttpContext.Current.Request.MapPath(HttpContext.Current.Request.ApplicationPath)
Or
HttpContext.Current.Request.MapPath("~/")

Request

HttpRequest.Params

Gets a combined collection of QueryString, Form, Cookies, and ServerVariables items.

Name-value pairs are added to the collection in the following order:

1. Query-string parameters.
2. Form fields.
3. Cookies.
4. Server variables.