asp.net - 请求在此上下文中不可用

Question

Exception Details: System.Web.HttpException: Request is not available in this context

Source Error:

Line 7:     Private Sub Application_Start(sender As Object, e As EventArgs)
Line 8:     ' Caching the tracker image in memory
Line 9:     Dim trackerImg As Byte() = File.ReadAllBytes(Context.Request.MapPath(ConfigurationManager.AppSettings("SD_Tut_ImageFileLocation")))
Line 10:    Application(ConfigurationManager.AppSettings("SD_Tut_ImageFileKeyName")) = trackerImg

第 9 行有错误

这是 Global.asax 代码

<%@ Application Language="vb" %>
<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="System.Collections.Generic" %>
<%@ Import Namespace="Stardeveloper.Tutorial" %>

<script runat="server">
   Private Sub Application_Start(sender As Object, e As EventArgs)
    ' Caching the tracker image in memory
    Dim trackerImg As Byte() = File.ReadAllBytes(Context.Request.MapPath(ConfigurationManager.AppSettings("SD_Tut_ImageFileLocation")))
    Application(ConfigurationManager.AppSettings("SD_Tut_ImageFileKeyName")) = trackerImg

    ' Creating a new request queue collection
    Dim queueCapacity As Integer = Convert.ToInt32(ConfigurationManager.AppSettings("SD_Tut_TrackerRequestsToCache"))
    Dim trackerReqQueue As New Queue(Of TrackerRequest)(queueCapacity)
    Application(ConfigurationManager.AppSettings("SD_Tut_TrackerCachedRequestsKeyName")) = trackerReqQueue
End Sub

Private Sub Application_End(sender As Object, e As EventArgs)
    ' Storing the queued tracker reqs to database
    Dim trackerReqQueue As Queue(Of TrackerRequest) = DirectCast(Application(ConfigurationManager.AppSettings("SD_Tut_TrackerCachedRequestsKeyName")), Queue(Of TrackerRequest))
    Tracker.FlushRequestQueueCache(trackerReqQueue)
End Sub

</script>

Answer 1

我们正在处理什么版本的 IIS？如果是 7 或更高版本，则所做的更改可能会导致此行为。

参见this article.