ASP.net开发opc客户端，aspx上数值不能显示。
我用asp.net+OPCDAAuto.dll想写网页来显示opc服务器里面的值。
这是LV3.aspx.vb里面的代码。
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Imports OPCAutomation
Partial Class _Default
  Inherits System.Web.UI.Page
  'Inherits System.Web.UI.Control
  Dim NUMITEMS As Integer = 24 ' 24 varialbes
  Dim WithEvents AnOPCServer As OPCAutomation.OPCServer
  Dim WithEvents ConnectedOPCServer As OPCAutomation.OPCServer
  Dim WithEvents ConnectedGroup As OPCAutomation.OPCGroup
  Dim OPCItemIDs(NUMITEMS) As String
  Dim ClientHandles(NUMITEMS) As Int32
  Dim ItemServerHandles As System.Array
  Dim AddItemServerErrors As System.Array
  Dim value1, value2 As Double

  Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
  Response.Redirect("LV4.aspx", True)
  End Sub

  Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
  Response.Redirect("LV3.aspx", True)
  End Sub

  Protected Sub form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles form1.Load
  Try
  ConnectedOPCServer = New OPCAutomation.OPCServer
  ConnectedOPCServer.Connect("Cybectec.VisualSubstation.1", "")
  Catch ex As Exception
  ConnectedOPCServer = Nothing
  MsgBox("OPC server connection encouter error: " + ex.Message)
  End Try
  Try
  ConnectedOPCServer.OPCGroups.DefaultGroupIsActive = True
  ConnectedOPCServer.OPCGroups.DefaultGroupDeadband = 0
  ConnectedGroup = ConnectedOPCServer.OPCGroups.Add("Equinix")
  ConnectedGroup.UpdateRate = 1000 ' update rate=10ms

  ConnectedGroup.IsSubscribed = True


  Catch ex As Exception
  MsgBox("OPC server add group encouter error: " + ex.Message)
  End Try

  Try
  Dim ItemCount As Integer = NUMITEMS
  Dim AddItemServerErrors As System.Array


  OPCItemIDs(1) = "PUE L3"
  ClientHandles(1) = 1

  OPCItemIDs(2) = "PUE L4"
  ClientHandles(2) = 2

  ConnectedGroup.OPCItems.DefaultIsActive = True

  ConnectedGroup.OPCItems.AddItems(ItemCount, OPCItemIDs, ClientHandles, ItemServerHandles, AddItemServerErrors)

  Catch ex As Exception
  ' Error handling
  MsgBox("OPC server add items encouter error: " + ex.Message)
  End Try

  End Sub
  Protected Sub ConnectedGroup_DataChange(ByVal TransactionID As Integer, ByVal NumItems As Integer, ByRef ClientHandles As System.Array, ByRef ItemValues As System.Array, ByRef Qualities As System.Array, ByRef TimeStamps As System.Array) Handles ConnectedGroup.DataChange
  value1 = ItemValues(1)
  value2 = ItemValues(2)
  End Sub

  Protected Sub Button3_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button3.Click
  OPCItemValue_1.Text = value1
  OPCItemValue_2.Text = value2
  End Sub
End Class
我一步一步调试的时候，在value1 = ItemValues(1)，value2 = ItemValues(2)这里看到是有值的。
然后我调用Button3_click的时候。
  Protected S