[DllImport("wininet.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern bool InternetSetCookie(string lpszUrlName, string lbszCookieName, string lpszCookieData);
然后在DocumentCompleted事件里
string[] strCookies = webbroser1.Document.Cookie.Split(new char[] { ';' });
for (int ci = 0; ci < strCookies.Length; ci++)
{
string[] strCookie = strCookies[ci].Split(new char[] { '=' });
InternetSetCookie(e.Url.ToString(), strCookie[0], "");
}