How to detect the Stop button selection in an ActiveX control in Visual C++ (167956)



The information in this article applies to:

  • The Microsoft Foundation Classes (MFC), when used with:
    • Microsoft Visual C++, 32-bit Enterprise Edition 4.2
    • Microsoft Visual C++, 32-bit Professional Edition 4.2
    • Microsoft Visual C++, 32-bit Enterprise Edition 4.2b
    • Microsoft Visual C++, 32-bit Professional Edition 4.2b
    • Microsoft Visual C++, 32-bit Enterprise Edition 5.0
    • Microsoft Visual C++, 32-bit Professional Edition 5.0
    • Microsoft Visual C++, 32-bit Enterprise Edition 6.0
    • Microsoft Visual C++, 32-bit Professional Edition 6.0
    • Microsoft Visual C++, 32-bit Learning Edition 6.0

This article was previously published under Q167956

SUMMARY

For some ActiveX controls, such as ActiveMovie, the Stop button in the toolbar of the Internet Explorer has special meaning to them. Those controls may want to stop playing the background sound or movie when the Stop button is clicked. This article shows how to add the IOleCommandTarget interface to an ActiveX control to trap the Stop button selection.

MORE INFORMATION

ActiveX controls typically do not support the IOleCommandTarget interface. For ActiveX controls that support IOleCommandTarget interface, you must add the following code to the .h and .cpp files of the COleControl-derived class. Then, you can trap the OLECMDID_STOP command id (id for the Stop button in Internet Explorer's toolbar) in the IOleCommandTarget::Exec()function.
   // In the .h file of COleControl-derived class:
   class CMyOleControl : public COleControl
   {
      ...

   // Interface Maps
   protected:

      // Add the following to support the IOleCommandTarget interface.
      // NOTE:  Nested class name is called CmdTargetObj
      DECLARE_INTERFACE_MAP()

      BEGIN_INTERFACE_PART(CmdTargetObj, IOleCommandTarget)
         STDMETHOD(QueryStatus)(const GUID*, ULONG, OLECMD[], OLECMDTEXT*);
         STDMETHOD(Exec)(const GUID*, DWORD, DWORD, VARIANTARG*,
            VARIANTARG*);
      END_INTERFACE_PART(CmdTargetObj)
   };


   // In the .cpp file of COleControl-derived class:
   BEGIN_INTERFACE_MAP(CMyOleControl, COleControl)
      INTERFACE_PART(CMyOleControl, IID_IOleCommandTarget, CmdTargetObj)
   END_INTERFACE_MAP()

   ULONG FAR EXPORT CMyOleControl::XCmdTargetObj::AddRef()
   {
      METHOD_PROLOGUE(CMyOleControl, CmdTargetObj)
      return pThis->ExternalAddRef();
   }

   ULONG FAR EXPORT CMyOleControl::XCmdTargetObj::Release()
   {
      METHOD_PROLOGUE(CMyOleControl, CmdTargetObj)
      return pThis->ExternalRelease();
   }

   HRESULT FAR EXPORT CMyOleControl::XCmdTargetObj::QueryInterface(
      REFIID iid, void FAR* FAR* ppvObj)
   {
      METHOD_PROLOGUE(CMyOleControl, CmdTargetObj)
      return (HRESULT)pThis->ExternalQueryInterface(&iid, ppvObj);
   }

   STDMETHODIMP CMyOleControl::XCmdTargetObj::QueryStatus(
      const GUID* pguidCmdGroup, ULONG cCmds, OLECMD rgCmds[],
      OLECMDTEXT* pcmdtext)
   {
      METHOD_PROLOGUE(CMyOleControl, CmdTargetObj)
      //... add YOUR own code here.

      return S_OK;
   }

   STDMETHODIMP CMyOleControl::XCmdTargetObj::Exec(
      const GUID* pguidCmdGroup, DWORD nCmdID, DWORD nCmdExecOpt,
      VARIANTARG* pvarargIn, VARIANTARG* pvarargOut)
   {
      METHOD_PROLOGUE(CMyOleControl, CmdTargetObj)
      if (nCmdID == OLECMDID_STOP)
         {
         // ... STOP button is clicked, add YOUR own code here.
         // We just display a message box.
         ::MessageBox(NULL, "STOP","CMyOleControl", MB_OK);
         }

      return S_OK;
   }
				

REFERENCES

For information about adding the IOleCommandTarget interface to the ActiveX control, refer to the "Interface Map Basics" section of "TN038: MFC/OLE IUnknown Implementation" in Visual C++ Books Online.

(c) Microsoft Corporation 1997, All Rights Reserved. Contributions by Yeong-Kah Tam, Microsoft Corporation

Modification Type:MajorLast Reviewed:6/2/2005
Keywords:kbinfo kbhowto KB167956 kbAudDeveloper