Vb.net Can'；t使用httpwebrequest加载页面

我想从以下地址获取航班时刻表：

{“BookingPathArguments”：null，“OriginDestinations”：[{“IsOpen”：false，“DataIdOrigin”：6337，“DataIdDestination”：6707，“DateTime”：“2016-04-27T00:00:00.000”；“TravelerTypes”：[{“DataId”：1，“TravelerCount”：1}，{“DataId”：2，“TravelerCount”：0}，{“DataId”：3，“TravelerCount”：0}]，“Currency”：{“Code”：“BDT”；“PromoCode”：null，“DisplayRealAvailability”：false，“可见性”：0，“ExtendedSearchDayCount”：3}

如果您将地址粘贴到浏览器地址栏并使用firebug（或任何fiddler），您将看到此页面发送3个jquery ajax调用以获取日程安排

PostData:SaleConditionAccepted=false&ExtendedSearchDayCount=3&DoNotCheckCache=false&AlreadyLoggedIn=false&TempDataGuid=NVES1YV4XOia40CmotiXof1&CurrencyCode=BDT&FareBasisDayTaid=&Travelers[0][DataId]=1&Travelers[0][Count 1&UserSelectedDate[0][SelectedDate]=2016-04-27T00:00:00&UserSelectedDate[0][DataIdOrigin]=6337&UserSelections[0][DataIdDestination]=6707&UserSelections[0][GenericClassDataId]=&UserSelections[0][SelectedSegments]=&JsonPrepareBookingRequest=&PromCode=

我正在使用httpwebrequest发送请求，但由于未知原因，我错过了会话。我使用CookieContainer保存cookies。我使用以下函数发送httprequest：

    Public Function GetPostWP(ByVal Url As String, ByVal CkCont As CookieContainer, Optional ByVal PostData As String = "", Optional ByVal refSite As String = "") As String
    Dim pStr As String = ""
    Try
        Dim Http As HttpWebRequest = WebRequest.Create(Url)
        If refSite <> "" Then Http.Referer = refSite
        Http.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate")

        Http.CookieContainer = CkCont  'Initial CkCont is Nothing
        Http.KeepAlive = True
        Http.AllowAutoRedirect = True

        'Http.UserAgent = "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2) Gecko/20100115 Firefox/3.6"
        Http.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
        Http.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.137 Safari/537.36"

        If PostData <> "" Then
            Http.Method = "POST"
            Http.ContentLength = PostData.Length
            Http.ContentType = "application/x-www-form-urlencoded"

            Dim PostStream As StreamWriter = New StreamWriter(Http.GetRequestStream())
            PostStream.Write(PostData)
            PostStream.Close()
        End If

        Using WebResponse As HttpWebResponse = Http.GetResponse()
            Dim responseStream As Stream = WebResponse.GetResponseStream()

            If (WebResponse.ContentEncoding.ToLower().Contains("gzip")) Then
                responseStream = New GZipStream(responseStream, CompressionMode.Decompress)
            ElseIf (WebResponse.ContentEncoding.ToLower().Contains("deflate")) Then
                responseStream = New DeflateStream(responseStream, CompressionMode.Decompress)
            End If

            Dim reader As StreamReader = New StreamReader(responseStream, Encoding.Default)
            pStr = reader.ReadToEnd()

            responseStream.Close()
        End Using

        tmpCky = CkCont 'tmpCky is a Public CookieContainer Variable to hold cookies for future use.
        GetPostWP = pStr

    Catch ex As Exception
        GetPostWP = "Error : " & ex.Message
    End Try
End Function

    Dim Cky As New CookieContainer
    Dim Txt as String = GetPostWP(PostAddress, Cky, PostData, RefAdd)

    Cky = tmpCky

公共函数GetPostWP（ByVal Url作为字符串，ByVal CkCont作为CookieContainer，可选ByVal PostData作为字符串=”，可选ByVal refSite作为字符串=”）作为字符串
Dim pStr As String=“”
尝试
Dim Http作为HttpWebRequest=WebRequest.Create（Url）
如果是refSite“”，则Http.Referer=refSite
Add（HttpRequestHeader.AcceptEncoding，“gzip，deflate”）
Http.CookieContainer=CkCont'初始CkCont为空
Http.KeepAlive=True
Http.AllowAutoRedirect=True
'Http.UserAgent=“Mozilla/5.0（Windows；U；Windows NT 5.1；en-US；rv:1.9.2）Gecko/20100115 Firefox/3.6”
Http.Accept=“text/html，application/xhtml+xml，application/xml；q=0.9，*/*；q=0.8“
Http.UserAgent=“Mozilla/5.0（Windows NT 6.1；WOW64）AppleWebKit/537.36（KHTML，类似Gecko）Chrome/34.0.1847.137 Safari/537.36”
如果PostData为“”，则
Http.Method=“POST”
Http.ContentLength=PostData.Length
Http.ContentType=“应用程序/x-www-form-urlencoded”
Dim PostStream As StreamWriter=新StreamWriter（Http.GetRequestStream（））
PostStream.Write（PostData）
PostStream.Close（）
如果结束
使用WebResponse作为HttpWebResponse=Http.GetResponse（）
Dim responseStream As Stream=WebResponse.GetResponseStream（）
如果（WebResponse.ContentEncoding.ToLower（）.包含（“gzip”）），则
responseStream=New GZipStream（responseStream，CompressionMode.decompresse）
ElseIf（WebResponse.ContentEncoding.ToLower（）.Contains（“deflate”））然后
responseStream=新的放气流（responseStream，压缩模式。解压缩）
如果结束
Dim reader As StreamReader=新StreamReader（responseStream，Encoding.Default）
pStr=reader.ReadToEnd（）
responseStream.Close（）
终端使用
tmpCky=CkCont'tmpCky是一个公共CookieContainer变量，用于保存Cookie以备将来使用。
GetPostWP=pStr
特例
GetPostWP=“错误：”&ex.消息
结束尝试
端函数
Dim Cky作为新的CookieContainer
Dim Txt as String=GetPostWP（PostAddress、Cky、PostData、RefAdd）
Cky=tmpCky

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有人可以分析该页面吗？

您是否尝试过不使用“Http.KeepAlive=True”我尝试过，但没有成功。该页面突然创建了一个RequestVerificationToken Cookie，这是我使用httpwebrequest无法获得的。是否有创建此Cookie的脚本？是否有专家？请回答。