c# - How to use HttpWebRequest.Credentials Property for Basic Authentication?

Question

How can I use the Webrequest Credentials Property to send an basic authentication header? Why isn't the Authorization header send with the request even whenPreAuthenticate is set to true?

WebRequest request = (HttpWebRequest)WebRequest.Create("https://api.github.com/user");
request.Credentials = new NetworkCredential("githubUsername", "githubPassword");
request.PreAuthenticate = true;
var response = request.GetResponse();

Answer 1

The server should send a HTTP 401 Not Authorized response code containing a WWW-Authenticate HTTP header.

WWW-Authenticate: Basic realm="example"

The PreAuthenticate property only works after authentication has taken place. From MSDN:

true to send an HTTP Authorization header with requests after authentication has taken place; otherwise, false. The default is false.

See other answers for more in depth explanation.