windows-nt/Source/XPSP1/NT/com/oleutest/letest/outline/dragdrop.c
2020-09-26 16:20:57 +08:00

675 lines
19 KiB
C

/*************************************************************************
**
** OLE 2 Sample Code
**
** dragdrop.c
**
** This file contains the major interfaces, methods and related support
** functions for implementing Drag/Drop. The code contained in this
** file is used by BOTH the Container and Server (Object) versions
** of the Outline sample code.
** The Drag/Drop support includes the following implementation objects:
**
** OleDoc Object
** exposed interfaces:
** IDropSource
** IDropTarget
**
** (c) Copyright Microsoft Corp. 1992 - 1993 All Rights Reserved
**
*************************************************************************/
#include "outline.h"
OLEDBGDATA
extern LPOUTLINEAPP g_lpApp;
#if defined( USE_DRAGDROP )
/* OleDoc_QueryDrag
* ----------------
* Check to see if Drag operation should be initiated. A Drag operation
* should be initiated when the mouse in either the top 10 pixels of the
* selected list box entry or in the bottom 10 pixels of the last selected
* item.
*/
BOOL OleDoc_QueryDrag(LPOLEDOC lpOleDoc, int y)
{
LPLINELIST lpLL = (LPLINELIST)&((LPOUTLINEDOC)lpOleDoc)->m_LineList;
LINERANGE LineRange;
if ( LineList_GetSel( lpLL, (LPLINERANGE)&LineRange) ) {
RECT rect;
if (!LineList_GetLineRect(lpLL,LineRange.m_nStartLine,(LPRECT)&rect))
return FALSE ;
if ( rect.top <= y && y <= rect.top + DD_SEL_THRESH )
return TRUE;
LineList_GetLineRect( lpLL, LineRange.m_nEndLine, (LPRECT)&rect );
if ( rect.bottom >= y && y >= rect.bottom - DD_SEL_THRESH )
return TRUE;
}
return FALSE;
}
/* OleDoc_DoDragScroll
* -------------------
* Check to see if Drag scroll operation should be initiated. A Drag scroll
* operation should be initiated when the mouse has remained in the active
* scroll area (11 pixels frame around border of window) for a specified
* amount of time (50ms).
*/
BOOL OleDoc_DoDragScroll(LPOLEDOC lpOleDoc, POINTL pointl)
{
LPOLEAPP lpOleApp = (LPOLEAPP)g_lpApp;
LPLINELIST lpLL = (LPLINELIST)&((LPOUTLINEDOC)lpOleDoc)->m_LineList;
HWND hWndListBox = LineList_GetWindow(lpLL);
DWORD dwScrollDir = SCROLLDIR_NULL;
DWORD dwTime = GetCurrentTime();
int nScrollInset = lpOleApp->m_nScrollInset;
int nScrollDelay = lpOleApp->m_nScrollDelay;
int nScrollInterval = lpOleApp->m_nScrollInterval;
POINT point;
RECT rect;
if ( lpLL->m_nNumLines == 0 )
return FALSE;
point.x = (int)pointl.x;
point.y = (int)pointl.y;
ScreenToClient( hWndListBox, &point);
GetClientRect ( hWndListBox, (LPRECT) &rect );
if (rect.top <= point.y && point.y<=(rect.top+nScrollInset))
dwScrollDir = SCROLLDIR_UP;
else if ((rect.bottom-nScrollInset) <= point.y && point.y <= rect.bottom)
dwScrollDir = SCROLLDIR_DOWN;
if (lpOleDoc->m_dwTimeEnterScrollArea) {
/* cursor was already in Scroll Area */
if (! dwScrollDir) {
/* cusor moved OUT of scroll area.
** clear "EnterScrollArea" time.
*/
lpOleDoc->m_dwTimeEnterScrollArea = 0L;
lpOleDoc->m_dwNextScrollTime = 0L;
lpOleDoc->m_dwLastScrollDir = SCROLLDIR_NULL;
} else if (dwScrollDir != lpOleDoc->m_dwLastScrollDir) {
/* cusor moved into a different direction scroll area.
** reset "EnterScrollArea" time to start a new 50ms delay.
*/
lpOleDoc->m_dwTimeEnterScrollArea = dwTime;
lpOleDoc->m_dwNextScrollTime = dwTime + (DWORD)nScrollDelay;
lpOleDoc->m_dwLastScrollDir = dwScrollDir;
} else if (dwTime && dwTime >= lpOleDoc->m_dwNextScrollTime) {
LineList_Scroll ( lpLL, dwScrollDir ); // Scroll doc NOW
lpOleDoc->m_dwNextScrollTime = dwTime + (DWORD)nScrollInterval;
}
} else {
if (dwScrollDir) {
/* cusor moved INTO a scroll area.
** reset "EnterScrollArea" time to start a new 50ms delay.
*/
lpOleDoc->m_dwTimeEnterScrollArea = dwTime;
lpOleDoc->m_dwNextScrollTime = dwTime + (DWORD)nScrollDelay;
lpOleDoc->m_dwLastScrollDir = dwScrollDir;
}
}
return (dwScrollDir ? TRUE : FALSE);
}
/* OleDoc_QueryDrop
** ----------------
** Check if the desired drop operation (identified by the given key
** state) is possible at the current mouse position (pointl).
*/
BOOL OleDoc_QueryDrop (
LPOLEDOC lpOleDoc,
DWORD grfKeyState,
POINTL pointl,
BOOL fDragScroll,
LPDWORD lpdwEffect
)
{
LPLINELIST lpLL = (LPLINELIST)&((LPOUTLINEDOC)lpOleDoc)->m_LineList;
LINERANGE linerange;
short nIndex = LineList_GetLineIndexFromPointl( lpLL, pointl );
DWORD dwScrollEffect = 0L;
DWORD dwOKEffects = *lpdwEffect;
/* check if the cursor is in the active scroll area, if so need the
** special scroll cursor.
*/
if (fDragScroll)
dwScrollEffect = DROPEFFECT_SCROLL;
/* if we have already determined that the source does NOT have any
** acceptable data for us, the return NO-DROP
*/
if (! lpOleDoc->m_fCanDropCopy && ! lpOleDoc->m_fCanDropLink)
goto dropeffect_none;
/* if the Drag/Drop is local to our document, we can NOT accept a
** drop in the middle of the current selection (which is the exact
** data that is being dragged!).
*/
if (lpOleDoc->m_fLocalDrag) {
LineList_GetSel( lpLL, (LPLINERANGE)&linerange );
if (linerange.m_nStartLine <= nIndex && nIndex<linerange.m_nEndLine)
goto dropeffect_none;
}
/* OLE2NOTE: determine what type of drop should be performed given
** the current modifier key state. we rely on the standard
** interpretation of the modifier keys:
** no modifier -- DROPEFFECT_MOVE or whatever is allowed by src
** SHIFT -- DROPEFFECT_MOVE
** CTRL -- DROPEFFECT_COPY
** CTRL-SHIFT -- DROPEFFECT_LINK
*/
*lpdwEffect = OleStdGetDropEffect(grfKeyState);
if (*lpdwEffect == 0) {
// No modifier keys given. Try in order MOVE, COPY, LINK.
if ((DROPEFFECT_MOVE & dwOKEffects) && lpOleDoc->m_fCanDropCopy)
*lpdwEffect = DROPEFFECT_MOVE;
else if ((DROPEFFECT_COPY & dwOKEffects) && lpOleDoc->m_fCanDropCopy)
*lpdwEffect = DROPEFFECT_COPY;
else if ((DROPEFFECT_LINK & dwOKEffects) && lpOleDoc->m_fCanDropLink)
*lpdwEffect = DROPEFFECT_LINK;
else
goto dropeffect_none;
} else {
/* OLE2NOTE: we should check if the drag source application allows
** the desired drop effect.
*/
if (!(*lpdwEffect & dwOKEffects))
goto dropeffect_none;
if ((*lpdwEffect == DROPEFFECT_COPY || *lpdwEffect == DROPEFFECT_MOVE)
&& ! lpOleDoc->m_fCanDropCopy)
goto dropeffect_none;
if (*lpdwEffect == DROPEFFECT_LINK && ! lpOleDoc->m_fCanDropLink)
goto dropeffect_none;
}
*lpdwEffect |= dwScrollEffect;
return TRUE;
dropeffect_none:
*lpdwEffect = DROPEFFECT_NONE;
return FALSE;
}
/* OleDoc_DoDragDrop
* -----------------
* Actually perform a drag/drop operation with the current selection in
* the source document (lpSrcOleDoc).
*
* returns the result effect of the drag/drop operation:
* DROPEFFECT_NONE,
* DROPEFFECT_COPY,
* DROPEFFECT_MOVE, or
* DROPEFFECT_LINK
*/
DWORD OleDoc_DoDragDrop (LPOLEDOC lpSrcOleDoc)
{
LPOUTLINEAPP lpOutlineApp = (LPOUTLINEAPP)g_lpApp;
LPOLEAPP lpOleApp = (LPOLEAPP)g_lpApp;
LPOUTLINEDOC lpSrcOutlineDoc = (LPOUTLINEDOC)lpSrcOleDoc;
LPOLEDOC lpDragDoc;
LPLINELIST lpSrcLL =
(LPLINELIST)&((LPOUTLINEDOC)lpSrcOleDoc)->m_LineList;
DWORD dwEffect = 0;
LPLINE lplineStart, lplineEnd;
LINERANGE linerange;
BOOL fPrevEnable1;
BOOL fPrevEnable2;
HRESULT hrErr;
OLEDBG_BEGIN3("OleDoc_DoDragDrop\r\n")
/* squirrel away a copy of the current selection to the ClipboardDoc */
lpDragDoc = (LPOLEDOC)OutlineDoc_CreateDataTransferDoc(lpSrcOutlineDoc);
if ( ! lpDragDoc) {
dwEffect = DROPEFFECT_NONE;
goto error;
}
/* OLE2NOTE: initially the DataTransferDoc is created with a 0 ref
** count. in order to have a stable Doc object during the drag/
** drop operation, we intially AddRef the Doc ref cnt and later
** Release it. This AddRef is artificial; it is simply
** done to guarantee that a harmless QueryInterface followed by
** a Release does not inadvertantly force our object to destroy
** itself prematurely.
*/
OleDoc_AddRef(lpDragDoc);
//NOTE: we need to keep the LPLINE pointers
// rather than the indexes because the
// indexes will not be the same after the
// drop occurs -- the drop adds new
// entries to the list thereby shifting
// the whole list.
LineList_GetSel( lpSrcLL, (LPLINERANGE)&linerange );
lplineStart = LineList_GetLine ( lpSrcLL, linerange.m_nStartLine );
lplineEnd = LineList_GetLine ( lpSrcLL, linerange.m_nEndLine );
if (! lplineStart || ! lplineEnd) {
dwEffect = DROPEFFECT_NONE;
goto error;
}
lpSrcOleDoc->m_fLocalDrop = FALSE;
lpSrcOleDoc->m_fLocalDrag = TRUE;
/* OLE2NOTE: it is VERY important to DISABLE the Busy/NotResponding
** dialogs BEFORE calling DoDragDrop. The DoDragDrop API starts
** a mouse capture modal loop. if the Busy/NotResponding comes
** up in the middle of this loop (eg. if one of the remoted
** calls like IDropTarget::DragOver call takes a long time, then
** the NotResponding dialog may want to come up), then the mouse
** capture is lost by OLE and things can get messed up.
*/
OleApp_DisableBusyDialogs(lpOleApp, &fPrevEnable1, &fPrevEnable2);
OLEDBG_BEGIN2("DoDragDrop called\r\n")
hrErr = DoDragDrop ( (LPDATAOBJECT) &lpDragDoc->m_DataObject,
(LPDROPSOURCE) &lpSrcOleDoc->m_DropSource,
DROPEFFECT_MOVE | DROPEFFECT_COPY | DROPEFFECT_LINK,
(LPDWORD) &dwEffect
);
OLEDBG_END2
// re-enable the Busy/NotResponding dialogs
OleApp_EnableBusyDialogs(lpOleApp, fPrevEnable1, fPrevEnable2);
#if defined( _DEBUG )
if (FAILED(hrErr))
OleDbgOutHResult("DoDragDrop returned", hrErr);
#endif
lpSrcOleDoc->m_fLocalDrag = FALSE;
/* OLE2NOTE: we need to guard the lifetime of our lpSrcOleDoc
** object while we are deleting the lines that were drag
** moved. it is possible that deleting these lines could
** cause the deletion of a PseudoObj. the deletion of a
** PseudoObj will cause the Doc to be unlock
** (CoLockObjectExternal(FALSE,TRUE) called). each PseudoObj
** holds a strong lock on the Doc. It is always best to have
** a memory guard around such critical sections of code. in
** this case, it is particularly important if we were an
** in-place active server and this drag ended up in a drop
** in our outer container. this scenario will lead to a
** crash if we do not hold this memory guard.
*/
OleDoc_Lock(lpSrcOleDoc, TRUE, 0);
/* if after the Drag/Drop modal (mouse capture) loop is finished
** and a drag MOVE operation was performed, then we must delete
** the lines that were dragged.
*/
if ( GetScode(hrErr) == DRAGDROP_S_DROP
&& (dwEffect & DROPEFFECT_MOVE) != 0 ) {
int i,j,iEnd;
LPLINE lplineFocusLine;
/* disable repainting and sending data changed notifications
** until after all lines have been deleted.
*/
OutlineDoc_SetRedraw ( (LPOUTLINEDOC)lpSrcOleDoc, FALSE );
/* if the drop was local to our document, then we must take
** into account that the line indices of the original source
** of the drag could have shifted because the dropped lines
** have been inserted into our document. thus we will
** re-determine the source line indices.
*/
if (lpSrcOleDoc->m_fLocalDrop) {
i = LineList_GetFocusLineIndex ( lpSrcLL );
lplineFocusLine = LineList_GetLine ( lpSrcLL, i );
}
for ( i = j = LineList_GetLineIndex(lpSrcLL,lplineStart ) ,
iEnd = LineList_GetLineIndex(lpSrcLL,lplineEnd ) ;
i <= iEnd ;
i++
) OutlineDoc_DeleteLine ((LPOUTLINEDOC)lpSrcOleDoc, j );
LineList_RecalcMaxLineWidthInHimetric(lpSrcLL, 0);
if (lpSrcOleDoc->m_fLocalDrop) {
i = LineList_GetLineIndex ( lpSrcLL, lplineFocusLine );
LineList_SetFocusLine ( lpSrcLL, (WORD)i );
}
OutlineDoc_SetRedraw ( (LPOUTLINEDOC)lpSrcOleDoc, TRUE );
/* if it is a local Drag/Drop move, we need to balance the
** SetRedraw(FALSE) call that was made in the implementation
** of IDropTarget::Drop.
*/
if (lpSrcOleDoc->m_fLocalDrop)
OutlineDoc_SetRedraw ( (LPOUTLINEDOC)lpSrcOleDoc, TRUE );
LineList_ForceRedraw ( lpSrcLL, FALSE );
}
OleDoc_Release(lpDragDoc); // rel artificial AddRef above
OleDoc_Lock(lpSrcOleDoc, FALSE, FALSE); // unlock artificial lock guard
OLEDBG_END3
return dwEffect;
error:
OLEDBG_END3
return dwEffect;
}
/*************************************************************************
** OleDoc::IDropSource interface implementation
*************************************************************************/
STDMETHODIMP OleDoc_DropSource_QueryInterface(
LPDROPSOURCE lpThis,
REFIID riid,
LPVOID FAR* lplpvObj
)
{
LPOLEDOC lpOleDoc = ((struct CDocDropSourceImpl FAR*)lpThis)->lpOleDoc;
return OleDoc_QueryInterface(lpOleDoc, riid, lplpvObj);
}
STDMETHODIMP_(ULONG) OleDoc_DropSource_AddRef( LPDROPSOURCE lpThis )
{
LPOLEDOC lpOleDoc = ((struct CDocDropSourceImpl FAR*)lpThis)->lpOleDoc;
OleDbgAddRefMethod(lpThis, "IDropSource");
return OleDoc_AddRef(lpOleDoc);
}
STDMETHODIMP_(ULONG) OleDoc_DropSource_Release ( LPDROPSOURCE lpThis)
{
LPOLEDOC lpOleDoc = ((struct CDocDropSourceImpl FAR*)lpThis)->lpOleDoc;
OleDbgReleaseMethod(lpThis, "IDropSource");
return OleDoc_Release(lpOleDoc);
}
STDMETHODIMP OleDoc_DropSource_QueryContinueDrag (
LPDROPSOURCE lpThis,
BOOL fEscapePressed,
DWORD grfKeyState
){
if (fEscapePressed)
return ResultFromScode(DRAGDROP_S_CANCEL);
else if (!(grfKeyState & MK_LBUTTON))
return ResultFromScode(DRAGDROP_S_DROP);
else
return NOERROR;
}
STDMETHODIMP OleDoc_DropSource_GiveFeedback (
LPDROPSOURCE lpThis,
DWORD dwEffect
)
{
// Tell OLE to use the standard drag/drop feedback cursors
return ResultFromScode(DRAGDROP_S_USEDEFAULTCURSORS);
#if defined( IF_SPECIAL_DD_CURSORS_NEEDED )
switch (dwEffect) {
case DROPEFFECT_NONE:
SetCursor ( ((LPOLEAPP)g_lpApp)->m_hcursorDragNone );
break;
case DROPEFFECT_COPY:
SetCursor ( ((LPOLEAPP)g_lpApp)->m_hcursorDragCopy );
break;
case DROPEFFECT_MOVE:
SetCursor ( ((LPOLEAPP)g_lpApp)->m_hcursorDragMove );
break;
case DROPEFFECT_LINK:
SetCursor ( ((LPOLEAPP)g_lpApp)->m_hcursorDragLink );
break;
}
return NOERROR;
#endif
}
/*************************************************************************
** OleDoc::IDropTarget interface implementation
*************************************************************************/
STDMETHODIMP OleDoc_DropTarget_QueryInterface(
LPDROPTARGET lpThis,
REFIID riid,
LPVOID FAR* lplpvObj
)
{
LPOLEDOC lpOleDoc = ((struct CDocDropTargetImpl FAR*)lpThis)->lpOleDoc;
return OleDoc_QueryInterface(lpOleDoc, riid, lplpvObj);
}
STDMETHODIMP_(ULONG) OleDoc_DropTarget_AddRef(LPDROPTARGET lpThis)
{
LPOLEDOC lpOleDoc = ((struct CDocDropTargetImpl FAR*)lpThis)->lpOleDoc;
OleDbgAddRefMethod(lpThis, "IDropTarget");
return OleDoc_AddRef(lpOleDoc);
}
STDMETHODIMP_(ULONG) OleDoc_DropTarget_Release ( LPDROPTARGET lpThis)
{
LPOLEDOC lpOleDoc = ((struct CDocDropTargetImpl FAR*)lpThis)->lpOleDoc;
OleDbgReleaseMethod(lpThis, "IDropTarget");
return OleDoc_Release(lpOleDoc);
}
STDMETHODIMP OleDoc_DropTarget_DragEnter (
LPDROPTARGET lpThis,
LPDATAOBJECT lpDataObj,
DWORD grfKeyState,
POINTL pointl,
LPDWORD lpdwEffect
)
{
LPOLEAPP lpOleApp = (LPOLEAPP)g_lpApp;
LPOLEDOC lpOleDoc = ((struct CDocDropTargetImpl FAR*)lpThis)->lpOleDoc;
LPLINELIST lpLL = (LPLINELIST)&((LPOUTLINEDOC)lpOleDoc)->m_LineList;
BOOL fDragScroll;
OLEDBG_BEGIN2("OleDoc_DropTarget_DragEnter\r\n")
lpOleDoc->m_fDragLeave = FALSE;
lpOleDoc->m_dwTimeEnterScrollArea = 0;
lpOleDoc->m_dwLastScrollDir = SCROLLDIR_NULL;
/* Determine if the drag source data object offers a data format
** that we can copy and/or link to.
*/
lpOleDoc->m_fCanDropCopy = OleDoc_QueryPasteFromData(
lpOleDoc,
lpDataObj,
FALSE /* fLink */
);
lpOleDoc->m_fCanDropLink = OleDoc_QueryPasteFromData(
lpOleDoc,
lpDataObj,
TRUE /* fLink */
);
fDragScroll = OleDoc_DoDragScroll ( lpOleDoc, pointl );
if (OleDoc_QueryDrop(lpOleDoc,grfKeyState,pointl,fDragScroll,lpdwEffect))
LineList_SetDragOverLineFromPointl( lpLL, pointl );
OLEDBG_END2
return NOERROR;
}
STDMETHODIMP OleDoc_DropTarget_DragOver (
LPDROPTARGET lpThis,
DWORD grfKeyState,
POINTL pointl,
LPDWORD lpdwEffect
)
{
LPOLEAPP lpOleApp = (LPOLEAPP)g_lpApp;
LPOLEDOC lpOleDoc = ((struct CDocDropTargetImpl FAR*)lpThis)->lpOleDoc;
LPLINELIST lpLL = (LPLINELIST)&((LPOUTLINEDOC)lpOleDoc)->m_LineList;
BOOL fDragScroll;
fDragScroll = OleDoc_DoDragScroll ( lpOleDoc, pointl );
if (OleDoc_QueryDrop(lpOleDoc,grfKeyState, pointl,fDragScroll,lpdwEffect))
LineList_SetDragOverLineFromPointl( lpLL, pointl );
else
LineList_RestoreDragFeedback( lpLL );
return NOERROR;
}
STDMETHODIMP OleDoc_DropTarget_DragLeave ( LPDROPTARGET lpThis)
{
LPOLEDOC lpOleDoc = ((struct CDocDropTargetImpl FAR*)lpThis)->lpOleDoc;
LPLINELIST lpLL = (LPLINELIST)&((LPOUTLINEDOC)lpOleDoc)->m_LineList;
OLEDBG_BEGIN2("OleDoc_DropTarget_DragLeave\r\n")
lpOleDoc->m_fDragLeave = TRUE;
LineList_RestoreDragFeedback( lpLL );
OLEDBG_END2
return NOERROR;
}
STDMETHODIMP OleDoc_DropTarget_Drop (
LPDROPTARGET lpThis,
LPDATAOBJECT lpDataObj,
DWORD grfKeyState,
POINTL pointl,
LPDWORD lpdwEffect
)
{
LPOLEDOC lpOleDoc = ((struct CDocDropTargetImpl FAR*)lpThis)->lpOleDoc;
LPLINELIST lpLL = (LPLINELIST)&((LPOUTLINEDOC)lpOleDoc)->m_LineList;
OLEDBG_BEGIN2("OleDoc_DropTarget_Drop\r\n")
lpOleDoc->m_fDragLeave = TRUE;
lpOleDoc->m_fLocalDrop = TRUE;
LineList_RestoreDragFeedback( lpLL );
SetFocus( LineList_GetWindow( lpLL) );
if (OleDoc_QueryDrop(lpOleDoc, grfKeyState, pointl, FALSE, lpdwEffect)) {
BOOL fLink = (*lpdwEffect == DROPEFFECT_LINK);
int iFocusLine = LineList_GetFocusLineIndex( lpLL );
BOOL fStatus;
OutlineDoc_SetRedraw ( (LPOUTLINEDOC)lpOleDoc, FALSE );
LineList_SetFocusLineFromPointl ( lpLL, pointl );
fStatus = OleDoc_PasteFromData(
lpOleDoc,
lpDataObj,
lpOleDoc->m_fLocalDrag, /* data source is local to app */
fLink
);
// if drop was unsuccessfull, restore the original focus line
if (! fStatus)
LineList_SetFocusLine( lpLL, (WORD)iFocusLine );
#if defined( INPLACE_CNTR )
{
LPCONTAINERDOC lpContainerDoc = (LPCONTAINERDOC)lpOleDoc;
/* OLE2NOTE: if there is currently a UIActive OLE object,
** then we must tell it to UIDeactivate after
** the drop has completed.
*/
if (lpContainerDoc->m_lpLastUIActiveLine) {
ContainerLine_UIDeactivate(
lpContainerDoc->m_lpLastUIActiveLine);
}
}
#endif
#if defined( INPLACE_SVR )
{
/* OLE2NOTE: if the drop was into a in-place visible
** (in-place active but NOT UIActive object), then we
** want to UIActivate the object after the drop is
** complete.
*/
ServerDoc_UIActivate((LPSERVERDOC) lpOleDoc);
}
#endif
/* if it is a local Drag/Drop move, don't enable redraw.
** after the source is done deleting the moved lines, it
** will re-enable redraw
*/
if (! (lpOleDoc->m_fLocalDrag
&& (*lpdwEffect & DROPEFFECT_MOVE) != 0 ))
OutlineDoc_SetRedraw ( (LPOUTLINEDOC)lpOleDoc, TRUE );
}
OLEDBG_END2
return NOERROR;
}
#endif // USE_DRAGDROP