怎么利用C#中的 webclient 创建cookie

Cookies are not limited only to web browsers. any http-aware client that supports cookies can deal with a cookie sending aSp .net Web api. the following code example shows a class extended from WebClient. it overrides the virtual method GetWebRequest to attach an instance of CookieContainer to the request. the CookieContainer object instance has to be reused across the requests to let it push cookies in the subsequent requests. For this reason, it is a class-level field and the same instance of the web client is used to send multiple requests. here we use a proxy of address localhost and port 8888, that of Fiddler, to inspect requests and responses.

public class CookieWebClient : WebClient {    private CookieContainer jar = new CookieContainer();
    protected override WebRequest GetWebRequest(Uri address)    {        WebRequest request = base.GetWebRequest(address);                     HttpWebRequest webRequest = request as HttpWebRequest;        if (webRequest != null)            webRequest.CookieContainer = jar;                     return request;    } }
string url = "http://localhost:7077/api/employees/12345"; 

Chapter 4 ■ http anatomy and SeCurity
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CookieWebClient client = new CookieWebClient() {    Proxy = new WebProxy("localhost", 8888)    // Fiddler };             Console.WriteLine(client.DownloadString(url)); // Cookie is created here Console.WriteLine(client.DownloadString(url)); //  In this request, the cookie gets sent back to the web API