webBrowser1.Document.Cookie取不到HttpOnly的Cookie，取Cookie不完整【转】

在做数据采集时，有些网站需要输入验证码，但各网站验证码都不同，不可能有完美的识别验证码的代码，所以我也没去研究，我所采取的方案是：在winform里通过WebBrowser调用网页先手动登录系统，然后再通过webBrowser1.Document.Cookie获取其Cookie，再将其用到HttpWebRequest里用来访问自己需要的页。

一直用的都没有问题，但最近在对一个网站操作时总是不能获取完整Cookie，百思不得其解，使用Fiddler2对比发现，不能获取到的Cookie里最后有一个HttpOnly的标识，顺藤摸瓜发现原来webBrowser1.Document.Cookie里是取不到HttpOnly的Cookie的，也找到解决方法：

 using System;
 using System.ComponentModel;
 using System.Net;
 using System.Runtime.InteropServices;
 using System.Security;
 using System.Security.Permissions;
 using System.Text;   

 internal sealed class NativeMethods
 {
     #region enums   

     public enum ErrorFlags
     {
         ERROR_INSUFFICIENT_BUFFER = ,
         ERROR_INVALID_PARAMETER = ,
         ERROR_NO_MORE_ITEMS =
     }   

     public enum InternetFlags
     {
         INTERNET_COOKIE_HTTPONLY = , //Requires IE 8 or higher
         INTERNET_COOKIE_THIRD_PARTY = ,
         INTERNET_FLAG_RESTRICTED_ZONE =
     }  

     #endregion  

     #region DLL Imports   

     [SuppressUnmanagedCodeSecurity, SecurityCritical, DllImport("wininet.dll", EntryPoint = "InternetGetCookieExW", CharSet = CharSet.Unicode, SetLastError = true, ExactSpelling = true)]
     internal static extern bool InternetGetCookieEx([In] string Url, [In] string cookieName, [Out] StringBuilder cookieData, [In, Out] ref uint pchCookieData, uint flags, IntPtr reserved);  

     #endregion
 }   

 /// <SUMMARY></SUMMARY>
 /// 取得WebBrowser的完整Cookie。
 /// 因为默认的webBrowser1.Document.Cookie取不到HttpOnly的Cookie
 ///
 public class FullWebBrowserCookie
 {   

     [SecurityCritical]
     public static string GetCookieInternal(Uri uri, bool throwIfNoCookie)
     {
         uint pchCookieData = ;
         string url = UriToString(uri);
         uint flag = (uint)NativeMethods.InternetFlags.INTERNET_COOKIE_HTTPONLY;   

         //Gets the size of the string builder
         if (NativeMethods.InternetGetCookieEx(url, null, null, ref pchCookieData, flag, IntPtr.Zero))
         {
             pchCookieData++;
             StringBuilder cookieData = new StringBuilder((int)pchCookieData);   

             //Read the cookie
             if (NativeMethods.InternetGetCookieEx(url, null, cookieData, ref pchCookieData, flag, IntPtr.Zero))
             {
                 DemandWebPermission(uri);
                 return cookieData.ToString();
             }
         }   

         int lastErrorCode = Marshal.GetLastWin32Error();   

         if (throwIfNoCookie || (lastErrorCode != (int)NativeMethods.ErrorFlags.ERROR_NO_MORE_ITEMS))
         {
             throw new Win32Exception(lastErrorCode);
         }   

         return null;
     }   

     private static void DemandWebPermission(Uri uri)
     {
         string uriString = UriToString(uri);   

         if (uri.IsFile)
         {
             string localPath = uri.LocalPath;
             new FileIOPermission(FileIOPermissionAccess.Read, localPath).Demand();
         }
         else
         {
             new WebPermission(NetworkAccess.Connect, uriString).Demand();
         }
     }   

     private static string UriToString(Uri uri)
     {
         if (uri == null)
         {
             throw new ArgumentNullException("uri");
         }   

         UriComponents components = (uri.IsAbsoluteUri ? UriComponents.AbsoluteUri : UriComponents.SerializationInfoString);
         return new StringBuilder(uri.GetComponents(components, UriFormat.SafeUnescaped), ).ToString();
     }
 }