activeX DLL 的编译问题

问题描述:
我在一个activeX dll中定义了一个类,将这个类作为其他各个dll与客户程序标志变量的公共载体,全局变量
在类中定义了一个timer 类型的变量g_timer2,以及一个control类型的变量g_MSCOMM,它作为一个对客户程序mscomm控件的引用,在其他dll中以及客户程序中都对该类在主程序中的对象进行了引用.在调试过程中,没有出现问题.
现在对该类进行编译,第一次在编译时选择no compatibility选项,生成gf.dll,二次编译选择binary compatibility选项,这时弹出'g_MSCOMM' in the 'Globalflags'class module has arguments and/or a return type that is incompatible with a similar declaration in the version compatible component.

Original definition:
Public g_MSCOMM As Object

Current definition:
Public g_MSCOMM As Control

Original definition:
Property Set g_MSCOMM(ByVal RHS As Object)

Current definition:
Public g_MSCOMM As Control

然后有两个选项 break compatibility 和 preserve compatibility

g_timer2也会出现同样的提示

我不明白究竟是哪里出了问题,这个向后兼容性究竟应该注意什么?我前后两次程序并没改动什么,g_MSCOMM,g_timer2的定义有问题吗?

Option Explicit

Public Offline As Boolean

Public SendingMsg As Boolean

Public SendAll As Boolean

Public langflag As Integer

Public FinishULData As Boolean

Public Iniflag As Boolean

Public FinishFlag As Boolean

Public PressStop As Boolean



Public Almshow As Boolean

Public SendFile As Boolean

Public AllowMoni As Boolean

Public FinishMoni As Boolean

Public SendPara As Boolean

Public Addr As Integer

Public addrStr1 As String

Public addrRecieve As String

Public ParaTabShow As Boolean



Public TestStyle As Integer

Public SparaExist As Boolean

Public reqTest As Boolean

Public DatAddr03 As String



Public coderight As Boolean

Public coderight1 As Boolean

Public ResumeFlag As Boolean

Public fftFlag As Boolean



Public message As String

Public AdjFlag As Integer

Public ServoType As String

Public TimerCount As Integer



Public g_MSCOMM As Control

Public g_Timer2 As Timer



Public MDIhwnd As Long

Public SpecialShow As Boolean

Public PhaseShow As Boolean

Public OperationShow As Boolean

Public LoadingShow As Boolean

Public JOGShow As Boolean

Public InertiaShow As Boolean

Public HandShow As Boolean

Public DMShow As Boolean

Public IMShow As Boolean

Public ScopeShow As Boolean



Public fftCmdShow As Boolean

Public fftGraphicShow As Boolean

Public testCmdShow As Boolean

Public testGraphicShow As Boolean

Public testParaShow As Boolean



Public Cn As ADODB.Connection



Public Function ProcessContinue(ByVal hwnd As Long) As Boolean

   If Not FinishULData Then

      If Not PressStop Then

         ProcessContinue = False

         MessageBoxEx hwnd, "UpLoad Plot Data", , MB_OK Or MB_ICONINFORMATION, LANG_ENGLISH

         Exit Function

      End If

   End If

   

   If SendPara Then

      ProcessContinue = False

      MessageBoxEx hwnd, "SendPara", ,MB_OK Or MB_ICONINFORMATION, LANG_ENGLISH

      Exit Function

   End If

   

   If fftFlag Then

      ProcessContinue = False

      MessageBoxEx hwnd, "fftFlag", , MB_OK Or MB_ICONINFORMATION, LANG_ENGLISH

      Exit Function

   End If

   

   

   ProcessContinue = True

   

End Function



Public Sub SendingMessage(ByVal msg As String)



   Dim Out1() As Byte  

   Dim Lrc As Long

   Dim a As Integer

   Dim L As Integer

   

   SendingMsg = True

   

   msg = addrStr1 & msg

   L = Len(msg)

   Dim i As Integer

   Lrc = 0

   

   For i = 0 To L / 2 - 1

     a = Val("&H" & Mid(msg, 2 * i + 1, 2))

     Lrc = a + Lrc

   Next

   

   Lrc = Lrc Mod 256

   Lrc = 256 - Lrc

   

   If Lrc = 256 Then

     Lrc = 0

   End If

   

   ReDim Out1(L + 4) As Byte

   For i = 1 To L

     Out1(i) = Asc(Mid(msg, i, 1))

   Next i

   

   If Lrc < 16 Then

     Out1(L + 1) = Asc(Mid("0" & Hex(Lrc), 1, 1))

     Out1(L + 2) = Asc(Mid("0" & Hex(Lrc), 2, 1))

   Else

     Out1(L + 1) = Asc(Mid(Hex(Lrc), 1, 1))

     Out1(L + 2) = Asc(Mid(Hex(Lrc), 2, 1))

   End If

   

   Out1(0) = Asc(":")

   Out1(L + 3) = &HD

   Out1(L + 4) = &HA

   

   If g_MSCOMM.PortOpen = True Then

      g_MSCOMM.OutBufferCount = 0

      g_MSCOMM.Output = Out1   '

   End If

   

End Sub