activeX DLL 的编译问题

[ly012659]

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

[东方之珠]

编译时选择二进制兼容模式。还有，你那些这是定义，如果不是供外部引用，就改成private。

[ly012659]

第一次编译时根本就不能选择二进制编译
还有我所有的public变量都是共用的
在与程序调试时没有问题,可是移除activex 工程,直接引用gf.dll时报错
Out of memory (Error 7),难道是我定义的类中的变量太多了?可是这些变量都是要与客户程序共用的啊,实现与客户程序的标志共用

[ly012659]

没人回贴~~~
可怜可怜,大侠们回个贴吧
是我问题叙述的不清楚吗?

[ly012659]

现在我将g_MSCOMM g_timer2定义为object重新编译,就没有break compatibility的提示出现了

g_timer2为什么不能定义为timer,g_MSCOMM 定义为control类型呢
将原来的一个类拆分为两个类,public变量分别定义在两个类里边就没有runtime error 7 out of memory 出现了

像这样将许多公共变量装在类中,它的弊端是什么呢

[Tiger_Zhao]

VB.Control 其实是 VB 内部的一个特殊类，它自动对控件进行封装让它们具有一定的共性。
比如用 MSComm 控件调用下面的函数可以正常工作，但是在其它编程环境中就不会有 .Parent 属性。

Private Sub f(ByVal c As Control)
    Debug.Print c.Parent.Name
    Debug.Print c.CommPort
End Sub

既然 VB 不支持将 Control 作为参数，那么声明为 Object 或 MSComm 都是可以的。

[东方之珠]

改成:

Public g_MSCOMM As Variant  

试一试

[ly012659]

没有人回答吗?
我等~~

[Tiger_Zhao]

在 COM 标准中没有公共变量，一个属性通过 {get_XXX, set_XXX, let_XXX} 等方法表示。
VB 自动将公共变量翻译为属性，所以接口中就有 Property Set g_MSCOMM(...)。

具体细节可用 Visual Studio 的工具 OLE View 打开 dll 查看。

[authenticationf]

不懂，up

[ly012659]

[Quote=引用 6 楼 Tiger_Zhao 的回复:]
既然 VB 不支持将 Control 作为参数，那么声明为 Object 或 MSComm 都是可以的。
[/Quote]


'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

既然可以声明为MSComm ,那为什么编译时会出现上述提示呢(如果声明为object就不会有这些东西出现了~~~) 而且出现
Original definition:
Property Set g_MSCOMM(ByVal RHS As Object) 我根本没有设置属性啊,编译器怎么判断出Original definition的是object类型.这究竟是怎么一种编译机制啊,很瞢~~~


还有to chenjl1031

第一次编译时根本选不了二进制编译(binary compatibility吧)啊,只有在no compatibility模式下编译生成一个gf.dll文件后才能进行二进制编译