// Name : wxIDropTarget::DragEnter
// Purpose : Called when the mouse enters the window (dragging something)
// Returns : S_OK
// Params : [in] IDataObject *pIDataSource : source data
// [in] DWORD grfKeyState : kbd & mouse state
// [in] POINTL pt : mouse coordinates
// [in/out]DWORD *pdwEffect : effect flag
// In: Supported effects
// Out: Resulting effect
// Notes :
STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
DWORD grfKeyState,
POINTL pt,
DWORD *pdwEffect)
{
wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::DragEnter"));
wxASSERT_MSG( m_pIDataObject == NULL,
wxT("drop target must have data object") );
// show the list of formats supported by the source data object for the
// debugging purposes, this is quite useful sometimes - please don't remove
#if 0
IEnumFORMATETC *penumFmt;
if ( SUCCEEDED(pIDataSource->EnumFormatEtc(DATADIR_GET, &penumFmt)) )
{
FORMATETC fmt;
while ( penumFmt->Next(1, &fmt, NULL) == S_OK )
{
wxLogDebug(wxT("Drop source supports format %s"),
wxDataObject::GetFormatName(fmt.cfFormat));
}
penumFmt->Release();
}
else
{
wxLogLastError(wxT("IDataObject::EnumFormatEtc"));
}
#endif // 0
if ( !m_pTarget->MSWIsAcceptedData(pIDataSource) ) {
// we don't accept this kind of data
*pdwEffect = DROPEFFECT_NONE;
return S_OK;
}
// for use in OnEnter and OnDrag calls
m_pTarget->MSWSetDataSource(pIDataSource);
// get hold of the data object
m_pIDataObject = pIDataSource;
m_pIDataObject->AddRef();
// we need client coordinates to pass to wxWin functions
if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
{
wxLogLastError(wxT("ScreenToClient"));
}
// give some visual feedback
*pdwEffect = ConvertDragResultToEffect(
m_pTarget->OnEnter(pt.x, pt.y, ConvertDragEffectToResult(
GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect))
)
);
return S_OK;
}
// Name : wxIDropTarget::Drop
// Purpose : Instructs the drop target to paste data that was just now
// dropped on it.
// Returns : S_OK
// Params : [in] IDataObject *pIDataSource the data to paste
// [in] DWORD grfKeyState kbd & mouse state
// [in] POINTL pt where the drop occurred?
// [in/out]DWORD *pdwEffect operation effect
// Notes :
STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
DWORD grfKeyState,
POINTL pt,
DWORD *pdwEffect)
{
wxLogTrace(wxTRACE_OleCalls, wxT("IDropTarget::Drop"));
// TODO I don't know why there is this parameter, but so far I assume
// that it's the same we've already got in DragEnter
wxASSERT( m_pIDataObject == pIDataSource );
// we need client coordinates to pass to wxWin functions
if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
{
wxLogLastError(wxT("ScreenToClient"));
}
// first ask the drop target if it wants data
if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
// it does, so give it the data source
m_pTarget->MSWSetDataSource(pIDataSource);
// and now it has the data
wxDragResult rc = ConvertDragEffectToResult(
GetDropEffect(grfKeyState, m_pTarget->GetDefaultAction(), *pdwEffect));
rc = m_pTarget->OnData(pt.x, pt.y, rc);
if ( wxIsDragResultOk(rc) ) {
// operation succeeded
*pdwEffect = ConvertDragResultToEffect(rc);
}
else {
*pdwEffect = DROPEFFECT_NONE;
}
}
else {
// OnDrop() returned false, no need to copy data
*pdwEffect = DROPEFFECT_NONE;
}
// release the held object
RELEASE_AND_NULL(m_pIDataObject);
return S_OK;
}