Q182598: HOWTO: Implement IObjectSafety in Visual Basic Controls
Article: Q182598
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.0,4.01,4.01 SP1,4.01 SP2,5,5.0,5.01,5.01 SP1,5.5,5.5 Service Pack 1,6.0
Operating System(s):
Keyword(s): kbActiveX kbVBp500 kbFAQ kbDSupport kbieFAQ
Last Modified: 13-SEP-2001
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The information in this article applies to:
- Microsoft Visual Basic Control Creation Edition for Windows, version 5.0
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0
- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0
- Microsoft Internet Explorer (Programming) versions 4.0, 4.01, 4.01 SP1, 4.01 SP2, 5, 5.01, 5.01 SP1, 5.5, 5.5 Service Pack 1
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SUMMARY
=======
This article describes how to implement the IObjectSafety interface in Visual
Basic controls to mark the controls safe for scripting and initialization. By
default, Visual Basic controls use component category entries in the registry to
mark the control safe for scripting and initialization. Implementing the
IObjectSafety interface is the preferred method. This article contains all the
code that is required to implement this interface in Visual Basic controls.
Please keep in mind that a control should only be marked as safe if it is, in
fact, safe. This article does not describe the details of marking controls as
safe for scripting and initialization; it simply demonstrates how to do it in
code. Please refer to the Internet Client Software Development Kit (SDK)
documentation for a detailed description of this. See "Safe Initialization and
Scripting for ActiveX Controls" under the Component Development section.
MORE INFORMATION
================
WARNING: One or more of the following functions are discussed in this article:
VarPtr, VarPtrArray, VarPtrStringArray, StrPtr, and ObjPtr. These functions are
not supported by Microsoft Technical Support. They are not documented in the
Visual Basic documentation and are provided in this Knowledge Base article "as
is." Microsoft does not guarantee that they will be available in future releases
of Visual Basic. For additional information about these functions, click the
article number below to view the article in the Microsoft Knowledge Base:
Q199824 HOWTO: Get the Address of Variables in Visual Basic
The following steps illustrate how to create a simple Visual Basic control and
mark it safe for scripting and initialization.
1. Create a new folder where you can save all files that you create in this
example.
2. Get the OLE Automation Type Library Generator from the Visual Basic CD-ROM.
To do this, copy all four files from the \Common\Tools\VB\Unsupprt\Typlib\
folder to your project folder.
3. Copy the following text into Notepad, and save the file in the project folder
as 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);
}
}
4. At a command prompt, use the "CD <path>" (without the quotation marks)
command to move to the project folder, and type the following command to
generate a .tlb file:
"MKTYPLIB objsafe.odl /tlb objsafe.tlb" (without the quotation marks)
5. From Visual Basic, create an ActiveX Control project. In the Properties list,
change the name of the project to IObjSafety and the name of the control to
DemoCtl. Put a CommandButton named cmdTest on the control. In the Click event
handler of the cmdTest, put a MsgBox "Test" statement.
6. On the Project menu, click References, browse to and add Objsafe.tlb, which
you created earlier.
7. Add a new module to your project with the following code, and name the module
basSafeCtl:
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
8. From Project Properties, change the Startup Object to "Sub Main" to execute
the Sub Main above. Use the m_fSafeForScripting and m_fSafeForInitializing
variables to specify the values of safe for the scripting and/or
initialization variables.
9. Open the code window of your control. Add the following line of code to the
Declaration section (right after Option Explicit or as the first):
Implements IObjectSafety
10. Copy the following two procedures to your controls code:
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
11. On the File menu, save your project and files. Make an OCX file from your
project. Your control now implements the IObjectSafety interface. To test
it, insert the control in an .htm file.
REFERENCES
==========
MkTypLib.exe is an old tool that previously shipped with the Platform Software
Development Kit (SDK) that comes with Microsoft Visual Studio 6.0. For
information on how to install the Platform SDK that comes with Visual Studio
6.0, see the following Microsoft Web site:
http://msdn.microsoft.com/library/psdk/sdkintro/usage_4rqu.htm
The current Platform SDK does not come with the MkTypLib.exe tool. For
information about what Microsoft products ship the Type Library Compiler
(MkTypLib.exe), see the following Microsoft DLL Help database and search on the
file name MkTypLib.exe
http://support.microsoft.com/servicedesks/fileversion/dllinfo.asp
For information about how to invoke MkTypLib, see the following Microsoft Web
site:
http://msdn.microsoft.com/library/psdk/automat/chap8_6cki.htm
For additional information, click the article numbers below to view the articles
in the Microsoft Knowledge Base:
Q161873 HOWTO: Mark MFC Controls Safe for Scripting/Initialization
Q143258 HOWTO: Create Constants and DLL Declarations in a Type Library
Q131105 SAMPLE: TYPEBLD: How to Use ICreateTypeLib and ICreateTypeInfo
For more information about the IObjectSafety interface, see the following
Microsoft Web site:
http://msdn.microsoft.com/workshop/components/com/reference/ifaces/iobjectsafety/iobjectsafety.asp
For more information about safe initialization and scripting for ActiveX
controls, see the following Microsoft Web site:
http://msdn.microsoft.com/workshop/components/activex/safety.asp
For more information on developing Web-based solutions for Internet Explorer,
please see the following Web sites:
http://msdn.microsoft.com/workshop/entry.asp
http://msdn.microsoft.com/ie/
http://support.microsoft.com/highlights/iep.asp?FR=0&SD=MSDN
Additional query words: safety scripting persistence initialization
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Keywords : kbActiveX kbVBp500 kbFAQ kbDSupport kbieFAQ
Technology : kbVBSearch kbIEsearch kbAudDeveloper kbZNotKeyword6 kbSDKIESearch kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500Search kbVB500 kbVB600 kbIE500Search kbZNotKeyword3 kbSDKIE400 kbSDKIE401 kbSDKIE401SP1 kbSDKIE401SP2 kbSDKIE501SP1 kbSDKIE550SP1 kbSDKIE500 kbSDKIE501 kbSDKIE550 kbIE550Search
Version : :4.0,4.01,4.01 SP1,4.01 SP2,5,5.0,5.01,5.01 SP1,5.5,5.5 Service Pack 1,6.0
Issue type : kbhowto
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