DragOver이벤트 발생시 LPDWORD pdwEffect의 값을 바꿔주시면 됩니다.
typedef enum tagDROPEFFECT
{
DROPEFFECT_NONE = 0,
DROPEFFECT_COPY = 1,
DROPEFFECT_MOVE = 2,
DROPEFFECT_LINK = 4,
DROPEFFECT_SCROLL = 0x80000000,
}DROPEFFECT;
These values have the following meaning:
DROPEFFECT name Value Description
DROPEFFECT_NONE 0 Drop target cannot accept the data.
DROPEFFECT_COPY 1 Drop results in a copy. The original data is untouched by the drag source.
DROPEFFECT_MOVE 2 Drag source should remove the data.
DROPEFFECT_LINK 4 Drag source should create a link to the original data.
DROPEFFECT_SCROLL 0x80000000 Scrolling is about to start or is currently occurring in the target. This value is used in addition to the other values.
사용예)
STDMETHODIMP TDropTarget::DragOver(DWORD grfKeyState, POINTL pt,
LPDWORD pdwEffect)
{
*pdwEffect=DROPEFFECT_COPY;//아이콘 모양이 화살표옆에 +가붙은 아이콘
return NOERROR;
}
이기주 님이 쓰신 글 :
: 답변감사합니다. 한가지더 질문입니다.
: DragOver인 상태에서의 아이콘 변경이 가능한지요.
: 가능하다면 방법을 알고 싶습니다.
:
:
: 유영인 [Chris] 님이 쓰신 글 :
: : 아래 OLE Drag&Drop 설명과 예제입니다..
: :
: :
: :
: : The WM_DROPFILES message is specifically meant for the transfer of files from
: : Explorer to an application. Using the message is simple, but as you've
: : discovered, it's limited. If you're looking to accept drops (i.e., data) from
: : other applications, you'll need to use OLE drag-drop. Most applications use OLE
: : for the transfer of data, so if you implement a "drop target" class, you will be
: : able to accept this data and receive notification of the standard OLE drag-drop
: : events (i.e., similar to OnDragEnter, OnDragOver, OnDrop, etc.). If you read
: : the following reference, you can cut and paste the TDropTarget class from the
: : CAQ and be up and running...
: :
: :
http://bcbcaq.freeservers.com/project_DD.html
: :
: : In the article, I specifically target file transfers from Explorer. That is,
: : the TDropTarget::HandleDrop(), DragEnter(), Drop(), and the TForm1::WMOleDrop()
: : member functions specifically deal with the CF_HDROP format. If you're looking
: : to accept text from browsers, you'll need to modify these functions to handle
: : the CF_TEXT format. So, read the CAQ, try to modify it for the CF_TEXT format,
: : then refer to the following example if you run into trouble...
: :
: : // in TDropTarget header...
: : // helper function -- modified for CF_TEXT
: : void __fastcall HandleDrop(const char* AText);
: :
: :
: : // in TDropTarget source...
: :
: : // helper routine to notify Form of drop on target
: : void __fastcall TDropTarget::HandleDrop(const char* AText)
: : {
: : SNDMSG(FFormHandle, WM_OLEDROP, reinterpret_cast<WPARAM>(AText), 0);
: : }
: :
: : // modified (for CF_TEXT) DragEnter
: : STDMETHODIMP TDropTarget::DragEnter(LPDATAOBJECT pDataObj, DWORD grfKeyState,
: : POINTL pt, LPDWORD pdwEffect)
: : {
: : FORMATETC fmtetc;
: : fmtetc.cfFormat = CF_TEXT;
: : fmtetc.ptd = NULL;
: : fmtetc.dwAspect = DVASPECT_CONTENT;
: : fmtetc.lindex = -1;
: : fmtetc.tymed = TYMED_HGLOBAL;
: :
: : // does the drag source provide CF_TEXT?
: : if (SUCCEEDED(pDataObj->QueryGetData(&fmtetc)))
: : {
: : FAcceptFormat = true;
: : *pdwEffect = DROPEFFECT_COPY;
: : }
: : else
: : {
: : FAcceptFormat = false;
: : *pdwEffect = DROPEFFECT_NONE;
: : }
: : return NOERROR;
: : }
: :
: : // modified (for CF_TEXT) Drop
: : STDMETHODIMP TDropTarget::Drop(LPDATAOBJECT pDataObj, DWORD grfKeyState,
: : POINTL pt, LPDWORD pdwEffect)
: : {
: : FORMATETC fmtetc;
: : fmtetc.cfFormat = CF_TEXT;
: : fmtetc.ptd = NULL;
: : fmtetc.dwAspect = DVASPECT_CONTENT;
: : fmtetc.lindex = -1;
: : fmtetc.tymed = TYMED_HGLOBAL;
: :
: : // user has dropped on us -- get the CF_TEXT data from drag source
: : STGMEDIUM medium;
: : HRESULT hr = pDataObj->GetData(&fmtetc, &medium);
: :
: : if (SUCCEEDED(hr))
: : {
: : // grab a pointer to the data
: : HGLOBAL HData = medium.hGlobal;
: : char* text = static_cast<char*>(GlobalLock(HData));
: : try
: : {
: : // call the helper routine which will
: : // notify the Form of the drop
: : HandleDrop(text);
: : }
: : catch (...)
: : {
: : // release the pointer to the memory
: : GlobalUnlock(HData);
: : ReleaseStgMedium(&medium);
: : }
: : // release the pointer to the memory
: : GlobalUnlock(HData);
: : ReleaseStgMedium(&medium);
: : }
: : else
: : {
: : *pdwEffect = DROPEFFECT_NONE;
: : return hr;
: : }
: : return NOERROR;
: : }
: :
: :
: : // in Form1 header...
: : #include "DropTarget.h"
: :
: : LPDROPTARGET lpDropTarget_;
: : void __fastcall WMOleDrop(TMessage& AMsg);
: :
: : BEGIN_MESSAGE_MAP
: : MESSAGE_HANDLER(WM_OLEDROP, TMessage, WMOleDrop)
: : END_MESSAGE_MAP(TForm)
: :
: :
: : // in Form1 source...
: :
: : __fastcall TForm1::TForm1(TComponent* Owner)
: : : TForm(Owner)
: : {
: : // initialize the OLE library
: : OleInitialize(NULL);
: :
: : // pass the handle to the Form in the constructor
: : // so TDropTarget knows which window to send the
: : // WM_OLEDROP message
: : lpDropTarget_ =
: : reinterpret_cast<LPDROPTARGET>(new TDropTarget(Handle));
: : CoLockObjectExternal(lpDropTarget_, true, true);
: :
: : // register the Memo as a drop target
: : RegisterDragDrop(Memo1->Handle, lpDropTarget_);
: : }
: :
: : __fastcall TForm1::~TForm1()
: : {
: : // remove the Memo from the list of drop targets
: : RevokeDragDrop(Memo1->Handle);
: :
: : // delete the TDropTarget instance
: : lpDropTarget_->Release();
: : CoLockObjectExternal(lpDropTarget_, false, true);
: :
: : // uninitialize the OLE library
: : OleUninitialize();
: : }
: :
: : void __fastcall TForm1::WMOleDrop(TMessage& AMsg)
: : {
: : const char* text = reinterpret_cast<const char*>(AMsg.WParam);
: : Memo1->Lines->Add(text);
: : }
: :
: :
: : HTH.
: :
: : Damon C. (TeamB)
: :
: :
: :
: : 이기주 님이 쓰신 글 :
: : : 탐색기에서 TreeView로 파일을 드래그 할 경우
: : :
: : : WM_DROPFILES메세지 처리를 하여 사용하고 있습니다.
: : :
: : : 하지만 이메세지는 마우스로 drop하였을 경우에만 발생되지
: : :
: : : 드래그 하는중에는 발생되지 않습니다.
: : :
: : : 제가 알고싶은것은 바로 drag하는 중인지를 어떻게 알아내는가 하는것입니다.
: : :
: : : 알고 계신분의 답변 부탁드립니다.
: : :
