CODEWITHSUNDEEP
c++buildertlistviewoledragdrop
Alfred Chen
Alfred Chen

Reputation: 179

How to release the mouse after calling DoDragDrop

I wrote a demo containing a TListView (m_ListView). It shows my files on the D:\ drive. If I drag a TListItem in m_ListView and drop it on the E:\ drive, the selected file will be copied to E:\. This works well, but something is wrong with the end of the drag.

When I do the drag&drop and release my left button when the mouse is hovering over E:\, there will be a shade like in this picture (the file has been copied!):

screenshot

To perform another drag&drop action, I have to click on my TListView again.

What should I do to eliminate this?

I tried using ReleaseCapture(), but that didn't work (or I didn't use it correctly).

Main code:

void _fastcall MC_OLEDragHelper::MyListStartDrag(TObject* vSender, TDragObject*& vDragObject)
{

    int tCount = (int)m_ListView->Items->Count;

    MT_FileList tFileList;
    for(int i=0; i<tCount; i++)
        {
        TListItem* tItem = m_ListView->Items->Item[i];
        if(false == tItem->Selected)
            continue;

        KKSTR tFileName = m_ListViewDragKit->OnItemDragOut(tItem);
        if(true == tFileName.empty())
            continue;

        tFileList.push_back(tFileName);
        }

    //Call DoDragDrop
    DropFiles(&tFileList, DROPEFFECT_COPY);

    return;
}

DropFiles() function:

bool MC_OLEDragHelper::DropFiles(MT_FileList* vFileList, DWORD vDesireEffect)
{
    if(false == m_Available)
        return false;

    if(0 == vFileList->size())
        return false;

    void* tDropfiles = (DROPFILES*)CreateFileDespListItem(vFileList);

    FORMATETC tFormatEtc     = {CF_HDROP, 0, DVASPECT_CONTENT, -1, TYMED_HGLOBAL};
    STGMEDIUM tStorageMedium = {TYMED_HGLOBAL, {(HBITMAP)tDropfiles}, 0};

    m_DragItemList->Add(&tFormatEtc, &tStorageMedium, 1);

    DWORD tDropEffect;
    DWORD tDragResult = DoDragDrop(m_DragItemList, m_DropSource, vDesireEffect, &tDropEffect);

    bool  tRetVal = false;
    if(tDragResult != DRAGDROP_S_DROP)
        goto WORK_END;

    if(tDropEffect == DROPEFFECT_NONE)
        goto WORK_END;

    tRetVal = true;

WORK_END:
    ReleaseStgMedium(&tStorageMedium);
    DestroyFileDespListItem(HGLOBAL(tDropfiles));

    m_ListView->EndDrag(true);
    return tRetVal;
}

Upvotes: 0

Views: 189

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