Extract HttpOnly cookies (can be with WebBrowser control)

Readme.md

Usage with WebBrowser control:

var cookies = WebHelper.GetGlobalCookies(webBrowser.Url.AbsoluteUri);

• Source: http://ycouriel.blogspot.com/2010/07/webbrowser-and-httpwebrequest-cookies.html

ExtractHttpOnlyCookie.cs

using System.Runtime.InteropServices;

public class WebHelper {

    [DllImport("wininet.dll", CharSet = CharSet.Auto, SetLastError = true)]
    static extern bool InternetGetCookieEx(string pchURL, string pchCookieName, StringBuilder pchCookieData, ref uint pcchCookieData, int dwFlags, IntPtr lpReserved);
    const int INTERNET_COOKIE_HTTPONLY = 0x00002000;
    
    public static string GetGlobalCookies(string uri)
    {
        uint datasize = 1024;
        StringBuilder cookieData = new StringBuilder((int)datasize);
        if (InternetGetCookieEx(uri, null, cookieData, ref datasize, INTERNET_COOKIE_HTTPONLY, IntPtr.Zero)
            && cookieData.Length > 0)
        {
            return cookieData.ToString().Replace(';', ',');
        }
        else
        {
            return null;
        }
    }

}

I know it's been 5 years, but it does not work for me. Can you tell me if it's still supposed to be functional, and if so, can u tell me what I am doing wrong.