Описание тега system.net.httpwebrequest

Provides an HTTP-specific implementation of the WebRequest, an abstract base class for the.NET Framework's request/response model for accessing data from the Internet class.

The HttpWebRequest class provides support for the properties and methods defined in WebRequest and for additional properties and methods that enable the user to interact directly with servers using HTTP.

HttpWebRequest exposes common HTTP header values sent to the Internet resource as properties, set by methods, or set by the system; the following table contains a complete list. You can set other headers in the Headers property as name/value pairs. Note that servers and caches may change or add headers during the request.

http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.aspx