在ActiveX控件中检测IE中STOP按钮的按下

许多ActiveX控件，比如：ActiveMovie, IE工具条中的Stop按钮对于他们来说有特别的意义。当Stop按钮下按时这些控件能够停止播放背景音乐或动画。这篇文章将告诉您在ActiveX控件中添加IOleCommandTarget接口来捕获Stop 按钮的动作。


周详内容
为了支持IOleCommandTarget接口您必须手工在COleControl派生类的.h 和.cpp文档中添加如下代码。然后，您能够在IOleCommandTarget::Exec()函数中捕获OLECMDID_STOP命令id (IE工具条中Stop 按钮的id)。具体代码如下：

// COleControl派生类的.h文档:
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)
};


//COleControl派生类的.cpp文档:
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;
}