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Please know that you can refer to the Tutorial below to generate the chart image using ASPPage ImageRenderMethod and can use either Session, cache and file as the ImageTransferMethod.

The ASP Page-based tutorials show how you can replace the built-in HttpHandler with custom ASP pages, thereby gaining extra control over the chart rendering mechanism. This method allows you to customize, for example, the behavior of the client and server caches, and IIS logging.

Both tutorials use the following ASP page to replace the HttpHandler mechanism, and differ only in the way they store the chart data. The code below can handle both Session and Cache transfers. It performs the exact same functions as the built-in HttpHandler, and should be useful as a starting point for your custom pages.

·      Visual Basic

Imports System

Imports System.Web

Imports System.Web.SessionState

Namespace AspPageSample
_

Public Class StreamResponse

Inherits System.Web.UI.Page

 Private Sub Page_Load(sender As Object, e As System.EventArgs)

  ' Determine how the image is transferred to this page

  Dim ses As String = Request("SessionID")   ' non null if session transfer

  Dim cac As String = Request("CacheID")     ' non null if cache transfer

  Dim del As String = Request("Delete")      ' non null if delete request

  Dim doDelete As Boolean = False

  

  ' Check the delete request status

  If Not (del Is Nothing) Then

   del = del.ToLower()

   doDelete = del = "t" Or del = "true"

  End If

  

  Dim image As Byte() = Nothing

  Dim imgtype As String = String.Empty

  Dim img As String = String.Empty

  Dim hsh As String = String.Empty

  

  If Not (ses Is Nothing) Then

   ' extract the image info from the session object

   img = ses + "_ImageBytes"

   hsh = ses + "_Hash"

   

   image = CType(Session(img), Byte())

   imgtype = CStr(Session(hsh))

   

   If doDelete Then

    Session.Remove(img)

    Session.Remove(hsh)

   End If

  Else

   If Not (cac Is Nothing) Then

    ' extract the image info from the Application cache

    img = cac + "_ImageBytes"

    hsh = cac + "_Hash"

    

    image = CType(Cache(img), Byte())

    imgtype = CStr(Cache(hsh))

    

    If doDelete Then

     Cache.Remove(img)

     Cache.Remove(hsh)

    End If

   End If

  End If

  If Not (image Is Nothing) And Not (imgtype Is Nothing) Then

   ' return the binary image to the client

   imgtype = "image/" + imgtype.Substring((imgtype.LastIndexOf("."c) + 1))

   Response.Clear()

   Response.Cache.SetExpires(DateTime.MinValue)  ' clear client cache

   Response.ContentType = imgtype

   Response.BinaryWrite(image)

   Response.Flush()

  End If

 End Sub

End Class

End Namespace