Imports OPC
Imports OPCDA
Imports OPCDA.NET

Public Class Demo
   Function ServerAccess() As String
      Dim Srv As OpcServer = New OpcServer()
      Dim rtc As Int32 = Srv.Connect("Advosol.SimDAServer.1")
      If HRESULTS.Failed(rtc) Then
         Return Srv.GetErrorString(rtc, 0)
      End If

      Dim srwGroup As SyncIOGroup = New SyncIOGroup(Srv)
      Dim Rslt As OPCItemState
      Dim rtc As Int32
      rtc = srwGroup.Read(OPCDATASOURCE.OPC_DS_CACHE, 
                          "SimulatedData.Step", Rslt)
      Dim retVal As String
      If HRESULTS.Failed(rtc) Then
         retVal = "Read error"
      Else
         retVal = "data=" + Rslt.DataValue.ToString()
      End If
      srwGroup.Dispose()
      Srv.Disconnect()
      Return retVal
   End Function

End Class
 

Imports System.Runtime.InteropServices
Imports Opc
Imports OPCDA
Imports OPCDA.NET

Public Class DemoOpc
   Inherits System.Windows.Forms.Form

   Public Function ServerAccess() As String
      Dim Srv As OpcServer = New OpcServer()
      Dim rtc As Int32 = Srv.Connect("Advosol.SimDAServer.1")
      If HRESULTS.Failed(rtc) Then
         Return Srv.GetErrorString(rtc, 0)
      End If
          
      Dim oGrp As OpcGroup
      Dim deadBand As Single = 0.0F
      Try
             oGrp = Srv.AddGroup("Grp1", True, 500, deadBand, 0, 0)
      Catch
             Return "Group could not be added"
      End Try
      Dim items As OPCItemDef() = {Nothing}
      items(0) = New OPCItemDef("SimulatedData.Step", 
                                True, 0, VarEnum.VT_BSTR)
      Dim addRslt As OPCItemResult()
      Dim rtc As Int16
      rtc = oGrp.AddItems(items, addRslt)

      If HRESULTS.Failed(rtc) Then
         Srv.Disconnect()
         Return "Error at AddItem"
      End If
      Dim iHnd As Int32() = {0}
      iHnd(0) = addRslt(0).HandleServer
      Dim rslt As OPCItemState()
      rtc = oGrp.Read(OPCDATASOURCE.OPC_DS_CACHE, iHnd, rslt)
      Dim retVal As String
      If HRESULTS.Failed(rtc) Then
         retVal = "Read error"
      Else
         If HRESULTS.Failed(rslt(0).Error) Then
            retVal = "Item Read error"
         Else
            retVal = "data=" + rslt(0).DataValue.ToString()
         End If
      End If
      oGrp.Remove(True)
      Srv.Disconnect()
      Return retVal
   End Function
End Class