登陆百度的代码  没有错误提示 但是登陆失败
Private Function CheckValidationResult(ByVal sender As Object, ByVal certificate As X509Certificate, ByVal chain As X509Chain, ByVal sslPolicyerrors As SslPolicyErrors) As Boolean

        Return True
    End Function
main sub
Dim uristr As String = "https://passport.baidu.com?login"
        Dim Cookies As New CookieContainer
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3
        Dim ServerCertificateValidationCallback As New RemoteCertificateValidationCallback(AddressOf CheckValidationResult)
              Dim poststr As String = "tpl_ok=&next_target=&tpl=mn&skip_ok=&aid=&need_pay=&need_coin=&pay_method=&u=http://www.baidu.com/index.php&return_method=get&more_param=tn=leizhen&ch=12&return_type=&psp_tt=0&password=*******&safeflg=0&username=********&verifycode="
        Dim data() As Byte = Encoding.GetEncoding("GB2312").GetBytes(poststr)
        Dim request As HttpWebRequest = CType(HttpWebRequest.Create(New Uri(uristr)), HttpWebRequest)

        request.ServicePoint.Expect100Continue = False

        request.Accept = "*/*"
        request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727; .NET CLR 3.0.04506.648; .NET CLR 3.5.21022)"
        request.Referer = "https://passport.baidu.com?login"
        request.ContentType = "application/x-www-form-urlencoded"
        request.ContentLength = data.Length
        request.KeepAlive = True
        request.CookieContainer = Cookies
        request.AllowAutoRedirect = True
        request.Timeout = 300000
        request.Method = "POST"

        Dim writer As Stream = request.GetRequestStream()
        writer.Write(data, 0, data.Length)
        writer.Flush()
        writer.Close()

        Dim response As HttpWebResponse = CType(request.GetResponse(), HttpWebResponse)

        Dim res As Stream = response.GetResponseStream()
        Dim reader As New StreamReader(res, Encoding.GetEncoding("GB2312"))
        Dim html As String = reader.ReadToEnd()

        reader.Close()
        res.Close()
        response.Close()
        Console.WriteLine(html)
        Console.ReadKey()
end sub