Delphi/C++Builder 2006 Import ActiveX Control Update

A bug was recently found when importing the Microsoft Message Queue 3.0 Object Library type library contained in the DLL mqoa.dll. When calling ITypeInfo.GetDocumentation we would fail with the error TYPE_E_ELEMENTNOTFOUND. It turns out that even though the documentation states that ITypeInfo.GetDocumentation can be called with NULL as the last four parameters that in some cases methods that don't contain a help string such as the case with the method IMSMQManagement.TransactionalStatus, NULL is required. Here is the IDL of the interface as seen from OLE View:

   interface IMSMQManagement : IDispatch
   {
       [id(00000000), helpstring("Method to initialize the MSMQManagement
         object.")]
       HRESULT Init(
                       [in, optional] VARIANT* Machine,
                       [in, optional] VARIANT* PathName,
                       [in, optional] VARIANT* FormatName);
       [id(0x00000001), propget, helpstring("Property that identifies the queue.
         The format name of a queue is generated by MSMQ when the queue is created, or
         generated later by  the application.")]
       HRESULT FormatName([out, retval] BSTR* pbstrFormatName);
       [id(0x00000002), propget, helpstring("Property returning the name of the
         relevant machine.")]
       HRESULT Machine([out, retval] BSTR* pbstrMachine);
       [id(0x00000003), propget, helpstring("Property returning the number of
         messages in a queue.")]
       HRESULT MessageCount([out, retval] long* plMessageCount);
       [id(0x00000004), propget, helpstring("Property indicating that the
         queue is known to be foreign, that it is known not to be foreign,
         or that its status in this regard is unknown.")]
       HRESULT ForeignStatus([out, retval] long* plForeignStatus);
       [id(0x00000005), propget, helpstring("Property indicating the type of a
         queue.")]
       HRESULT QueueType([out, retval] long* plQueueType);
       [id(0x00000006), propget, helpstring("Property indicating whether the
         queue resides on the local machine.")]
       HRESULT IsLocal([out, retval] VARIANT_BOOL* pfIsLocal);
       [id(0x00000007), propget]
       HRESULT TransactionalStatus([out, retval] long* plTransactionalStatus);
       [id(0x00000008), propget, helpstring("Property indicating the amount of
         storage used for the queue.")]
       HRESULT BytesInQueue([out, retval] VARIANT* pvBytesInQueue);
   };

So now the code has been changed from:

 OleCheck(FParent.FTypeInfo.GetDocumentation(FuncDesc.memid, @Name, @HelpString,
   @FHelpContext, nil));

To the slightly more complicated:

 Check := FParent.FTypeInfo.GetDocumentation(FuncDesc.memid, @Name, @HelpString,
   @FHelpContext, nil);

 if Check = TYPE_E_ELEMENTNOTFOUND then
 begin
   OleCheck(FParent.FTypeInfo.GetDocumentation(FuncDesc.memid, @Name, nil,
     nil, nil));
 end
 else
   OleCheck(Check);

If you are getting an "element not found" error when using the Microsoft Message Queue 3.0 Object Library type library then you can download an unofficial update of tlib100.bpl here.