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如何在VB中实现ActiveX控件的IobjectSafety接口
发表日期:2006-05-01作者:[转贴] 出处:  

总述
本文叙述了如何在VB中实现控件的IobjectSafety接口,以标志该控件是脚本安全和初始化安全的。VB控件默认的处理方式是在注册表中注册组件类来标识其安全性,但实现IobjectSafety接口是更好的方法。本言语包括了实现过程中所需的所有代码。

请注意,控件只有确确实实是安全的,才能被标识为“安全的”。本文并未论及如何确保控件的安全性,这个问题请参阅Internet Client Software Development Kit (SDK)中的相关文档 "Safe Initialization and Scripting for ActiveX Controls",它在Component Development 栏目中。

 

相关信息:
<此处略去了一段也许无关紧要的警告>

现在开始循序渐进地举例说明怎样创建一个简单的VB控件,以及怎样将它标识为脚本安全和初始化安全。
首先新建一个文件夹来存放在本例中所产生的文件。

从VB CD-ROM取得OLE 自动化类库的制作工具。将VB安装光盘中\Common\Tools\VB\Unsupprt\Typlib\目录下所有内容一并拷贝到前面新建的项目文件夹中。


把下列内容拷贝到“记事本”中,然后保存到上述文件夹,文件名为Objsafe.odl:


      [
          uuid(C67830E0-D11D-11cf-BD80-00AA00575603),
          helpstring("VB IObjectSafety Interface"),
          version(1.0)
      ]
      library IObjectSafetyTLB
      {
          importlib("stdole2.tlb");
          [
              uuid(CB5BDC81-93C1-11cf-8F20-00805F2CD064),
              helpstring("IObjectSafety Interface"),
              odl
          ]
          interface IObjectSafety:IUnknown {
              [helpstring("GetInterfaceSafetyOptions")]
              HRESULT GetInterfaceSafetyOptions(
                        [in]  long  riid,
                        [in]  long *pdwSupportedOptions,
                        [in]  long *pdwEnabledOptions);

              [helpstring("SetInterfaceSafetyOptions")]
              HRESULT SetInterfaceSafetyOptions(
                        [in]  long  riid,
                        [in]  long  dwOptionsSetMask,
                        [in]  long  dwEnabledOptions);
           }
       }
在命令行提示符下切换到项目文件夹,输入下列命令创建一个.tlb 文件:


MKTYPLIB objsafe.odl /tlb objsafe.tlb
在VB中新建一个ActiveX Control 项目。修改属性,把项目命名为IobjSafety,控件命名为DemoCtl。在控件上放置一个按钮,命名为cmdTest,在它的Click事件中加入一句代码 MsgBox "Test" 。


打开菜单“工程->引用”,点“浏览”,找到刚刚建立的Objsafe.tlb,把它加入到引用中。


增加一个新module名为basSafeCtl,并在其中加入下列代码:


      Option Explicit

      Public Const IID_IDispatch = "{00020400-0000-0000-C000-000000000046}"
      Public Const IID_IPersistStorage = _
        "{0000010A-0000-0000-C000-000000000046}"
      Public Const IID_IPersistStream = _
        "{00000109-0000-0000-C000-000000000046}"
      Public Const IID_IPersistPropertyBag = _
        "{37D84F60-42CB-11CE-8135-00AA004BB851}"

      Public Const INTERFACESAFE_FOR_UNTRUSTED_CALLER = &H1
      Public Const INTERFACESAFE_FOR_UNTRUSTED_DATA = &H2
      Public Const E_NOINTERFACE = &H80004002
      Public Const E_FAIL = &H80004005
      Public Const MAX_GUIDLEN = 40

      Public Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
         (pDest As Any, pSource As Any, ByVal ByteLen As Long)
      Public Declare Function StringFromGUID2 Lib "ole32.dll" (rguid As _
         Any, ByVal lpstrClsId As Long, ByVal cbMax As Integer) As Long

      Public Type udtGUID
          Data1 As Long
          Data2 As Integer
          Data3 As Integer
          Data4(7) As Byte
      End Type

      Public m_fSafeForScripting As Boolean
      Public m_fSafeForInitializing As Boolean

      Sub Main()
          m_fSafeForScripting = True
          m_fSafeForInitializing = True
      End Sub
在工程属性中把启动对象改成Sub Main确保上述代码会被执行。m_fSafeForScripting 和m_fSafeForInitializing两件变量的值分别指定了脚本安全和初始化安全取值。


打开控件代码窗口,在声明部分加入如下代码(如果有Option Explicit语句,当然要保证代码放在其后):


Implements IObjectSafety
把下面两个过程代码拷贝到控件代码中:


      Private Sub IObjectSafety_GetInterfaceSafetyOptions(ByVal riid As _
      Long, pdwSupportedOptions As Long, pdwEnabledOptions As Long)

          Dim Rc      As Long
          Dim rClsId  As udtGUID
          Dim IID     As String
          Dim bIID()  As Byte

          pdwSupportedOptions = INTERFACESAFE_FOR_UNTRUSTED_CALLER Or _
                                INTERFACESAFE_FOR_UNTRUSTED_DATA

          If (riid <> 0) Then
              CopyMemory rClsId, ByVal riid, Len(rClsId)

              bIID = String$(MAX_GUIDLEN, 0)
              Rc = StringFromGUID2(rClsId, VarPtr(bIID(0)), MAX_GUIDLEN)
              Rc = InStr(1, bIID, vbNullChar) - 1
              IID = Left$(UCase(bIID), Rc)

              Select Case IID
                  Case IID_IDispatch
                      pdwEnabledOptions = IIf(m_fSafeForScripting, _
                    INTERFACESAFE_FOR_UNTRUSTED_CALLER, 0)
                      Exit Sub
                  Case IID_IPersistStorage, IID_IPersistStream, _
                     IID_IPersistPropertyBag
                      pdwEnabledOptions = IIf(m_fSafeForInitializing, _
                    INTERFACESAFE_FOR_UNTRUSTED_DATA, 0)
                      Exit Sub
                  Case Else
                      Err.Raise E_NOINTERFACE
                      Exit Sub
              End Select
          End If
      End Sub

      Private Sub IObjectSafety_SetInterfaceSafetyOptions(ByVal riid As _
      Long, ByVal dwOptionsSetMask As Long, ByVal dwEnabledOptions As Long)
          Dim Rc          As Long
          Dim rClsId      As udtGUID
          Dim IID         As String
          Dim bIID()      As Byte

          If (riid <> 0) Then
              CopyMemory rClsId, ByVal riid, Len(rClsId)

              bIID = String$(MAX_GUIDLEN, 0)
              Rc = StringFromGUID2(rClsId, VarPtr(bIID(0)), MAX_GUIDLEN)
              Rc = InStr(1, bIID, vbNullChar) - 1
              IID = Left$(UCase(bIID), Rc)

              Select Case IID
                  Case IID_IDispatch
                      If ((dwEnabledOptions And dwOptionsSetMask) <> _
                   INTERFACESAFE_FOR_UNTRUSTED_CALLER) Then
                          Err.Raise E_FAIL
                          Exit Sub
                      Else
                          If Not m_fSafeForScripting Then
                              Err.Raise E_FAIL
                          End If
                          Exit Sub
                      End If

                  Case IID_IPersistStorage, IID_IPersistStream, _
                IID_IPersistPropertyBag
                      If ((dwEnabledOptions And dwOptionsSetMask) <> _
                    INTERFACESAFE_FOR_UNTRUSTED_DATA) Then
                          Err.Raise E_FAIL
                          Exit Sub
                      Else
                          If Not m_fSafeForInitializing Then
                              Err.Raise E_FAIL
                          End If
                          Exit Sub
                      End If

                  Case Else
                      Err.Raise E_NOINTERFACE
                      Exit Sub
              End Select
          End If
      End Sub
保存后,把工程编译成OCX文件。现在控件已经实现了IObjectSafety 接口。在.htm中加入这件控件试一试吧。


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