Invoking ActiveX Objects

ActiveX objects can be invoked using Microsoft® Visual Basic®, C/C++, and VC5 with #import.

The following example shows how to create a queue using Visual Basic, VC5 with #import, and C.

Using Visual Basic

dim qinfo as New MSMQQueueInfo

on error goto ErrHandler
qinfo.PathName = ".\queuename"
qinfo.Create
Exit Function
ErrHandler:
   ' handle Create error

Using VC5 and #import

Using VC5 with #import provides an easy-to-use syntax that is similar to the syntax provided by Visual Basic. This syntax provides:

HRESULT to exception mapping. A VC5/ActiveX application can use try and catch to handle errors instead of testing for return values.
Support for optional parameters (not available in C/C++ implementations).
Reference counting and Query Interface supportso there is no need for explicit AddRef/QueryInterface.

#import "mqoa.dll;

   try {
       IMSMQQueueInfoPtr pqinfo ("MSMQ.MSMQQueueInfo");
       pqinfo->PutPathName (L".\queuename");
       //
       // Create non-transactional, non-world-readable queue.
       //
       pqinfo->Create();
       catch (_com_error &e) {
            // UNDONE: handle error.
            }
       }

Using C/C++

    IMSMQQueueInfo *pqinfo;

    HRESULT hresult;
    VARIANT varIsTransactional;
    VARIANT varIsWorldReadable;
    //
    // Create MSMQQueueInfo object
    //
    hresult = CoCreateInstance(
                   CLSID_MSMQQueueInfo,
                   NULL,                    // punkOuter
                   CLSCTX_SERVER,
                   IID_IMSMQQueueInfo,
                   (LPVOID *)&pqinfo
                   );
    if (SUCCEEDED(hresult)) {
      // Set the PathName.
      pqinfo->put_PathName(L".\queuename");
      //
      // specify if transactional
      //
      VariantInit(&varIsTransactional);
      varIsTransactional.vt = VT_BOOL;
      varIsTransactional.boolVal = MQ_TRANSACTIONAL_NONE;
      VariantInit(&varIsWorldReadable);
      varIsWorldReadable.vt = VT_BOOL;
      varIsWorldReadable.boolVal = FALSE;
      //
      // create the queue
      //
      hresult = pqinfo->Create(&varIsTransactional, 
                               &varIsWorldReadable);
      //
      // UNDONE: need to handle failure...
      //
    }