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Call this member function to retrieve a pointer to an unknown OLE control.

LPUNKNOWN GetControlUnknown( );

A pointer to the IUnknown interface of the OLE control represented by this CWnd object. If this object does not represent an OLE control, the return value is NULL.

You should not release this IUnknown pointer. Typically, you would use to obtain a specific interface of the control.

The interface pointer returned by GetControlUnknown is not reference-counted. Do not call IUnknown::Release on the pointer unless you have previously called IUnknown::AddRef on it.

// The following code fragment is taken from CMyDlg::OnInitDialog 
// CMyDlg is a CDialog-derived class. 

// IDC_MSACALCTRL1 is the ID of the Calendar control OCX embedded  
// on this dialog
CWnd *pWndCal = GetDlgItem(IDC_MSACALCTRL1);

// Use the IUnknown of the control
LPUNKNOWN pUnk = pWndCal->GetControlUnknown();

// From there get the IDispatch interface of control
pUnk->QueryInterface(IID_IDispatch, (LPVOID*)&pDisp);

// use IDispatch method to invoke the control's functionality

Header: afxwin.h