OLEDrag Sample (C++)
This sample illustrates drag & drop (using OLE mechanisms) within a tree control and with Windows Explorer.
The source code is located at C:\Program Files (x86)\Softelvdm\SftTree DLL 7.5\Samples\MFC\OLEDrag\SamplVw.cpp or C:\Program Files\Softelvdm\SftTree DLL 7.5\Samples\MFC\OLEDrag\SamplVw.cpp (on 32-bit Windows versions).
/****************************************************************************/
/* SftTree/DLL 7.5 - Tree Control for C/C++ */
/* Copyright (C) 1995, 2016 Softel vdm, Inc. All Rights Reserved. */
/****************************************************************************/
#include "stdafx.h"
#include "OLEDrag.h"
#include "sampldoc.h"
#include "samplvw.h"
#ifdef _DEBUG
#undef THIS_FILE
static char BASED_CODE THIS_FILE[] = __FILE__;
#endif
/////////////////////////////////////////////////////////////////////////////
// CSampleView
IMPLEMENT_DYNCREATE(CSampleView, CView)
BEGIN_MESSAGE_MAP(CSampleView, CView)
//{{AFX_MSG_MAP(CSampleView)
ON_WM_CREATE()
ON_WM_SIZE()
//}}AFX_MSG_MAP
ON_SFTTREEN_LBUTTONDBLCLK_TEXT(IDC_TREE, OnLButtonExpandCollapse)
ON_SFTTREEN_LBUTTONDOWN_BUTTON(IDC_TREE, OnLButtonExpandCollapse)
ON_SFTTREEN_LBUTTONDBLCLK_BUTTON(IDC_TREE, OnLButtonExpandCollapse)
ON_SFTTREEN_EXPANDALL(IDC_TREE, OnExpandAll)
ON_SFTTREEN_LBUTTONDBLCLK_COLUMNRES(IDC_TREE, OnLButtonDblClkColumnResize)
ON_SFTTREEN_LBUTTONDBLCLK_PLUSMIN(IDC_TREE, OnLButtonExpandCollapse)
ON_SFTTREEN_LBUTTONDOWN_PLUSMIN(IDC_TREE, OnLButtonExpandCollapse)
ON_SFTTREEN_BEGINDRAG(IDC_TREE, OnBeginDrag)
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CSampleView construction/destruction
CSampleView::CSampleView()
{
}
CSampleView::~CSampleView()
{
}
/////////////////////////////////////////////////////////////////////////////
// CSampleView drawing
void CSampleView::OnDraw(CDC* pDC)
{
CSampleDoc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
}
/////////////////////////////////////////////////////////////////////////////
// CSampleView diagnostics
#ifdef _DEBUG
void CSampleView::AssertValid() const
{
CView::AssertValid();
}
void CSampleView::Dump(CDumpContext& dc) const
{
CView::Dump(dc);
}
CSampleDoc* CSampleView::GetDocument() // non-debug version is inline
{
ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CSampleDoc)));
return (CSampleDoc*)m_pDocument;
}
#endif //_DEBUG
/////////////////////////////////////////////////////////////////////////////
// CSampleView message handlers
int CSampleView::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CView::OnCreate(lpCreateStruct) == -1)
return -1;
if (!m_Tree.CreateEx(
WS_EX_CLIENTEDGE,
SFTTREESTYLE_NOTIFY | /* Notify parent window */
SFTTREESTYLE_DRAGDROP | /* Drag & drop enabled */
SFTTREESTYLE_LEFTBUTTONONLY | /* Only respond to left mouse button */
SFTTREESTYLE_SCROLL | /* Honor WS_H/VSCROLL */
SFTTREESTYLE_DISABLENOSCROLL | /* Disable scrollbars instead of hiding */
WS_HSCROLL | WS_VSCROLL | /* Vertical and horizontal scrollbars */
WS_VISIBLE | WS_CHILD, /* Visible, child window */
CRect(0,0,0,0), /* Location */
this, /* Parent window */
IDC_TREE)) /* Tree control ID */
return -1;
m_Tree.SetShowHeader(TRUE); /* Show column headers */
SFT_PICTURE Pic; /* Used for certain pictures */
/* Register the . These pictures are used */
/* for all items in the tree control. All three pictures */
/* must be the same size. */
{
SFT_PICTURE aPic[3];
Sft_InitPicture(&aPic[0]);
Sft_InitPicture(&aPic[1]);
Sft_InitPicture(&aPic[2]);
m_aThreeItemBitmaps[0].LoadBitmap(IDB_EXPANDABLE);/* Expandable bitmap */
Sft_SetPictureBitmap(&aPic[0], m_aThreeItemBitmaps[0]);/* Assign bitmap */
m_aThreeItemBitmaps[1].LoadBitmap(IDB_EXPANDED);/* Expanded bitmap */
Sft_SetPictureBitmap(&aPic[1], m_aThreeItemBitmaps[1]);/* Assign bitmap */
m_aThreeItemBitmaps[2].LoadBitmap(IDB_LEAF);/* bitmap */
Sft_SetPictureBitmap(&aPic[2], m_aThreeItemBitmaps[2]);/* Assign bitmap */
m_Tree.SetPictures(aPic); /* Use */
}
m_Tree.SetItemBitmapAlign(TRUE); /* Align item bitmaps */
/* Register the size. All used */
/* must be the same size. Only one picture needs to be */
/* registered, even if several are used. */
{
SFTTREE_CELLINFOPARM CellInfo;
CellInfo.version = 7;
CellInfo.index = -1; /* Registering picture size */
m_CellBitmap.LoadBitmap(IDB_SMILE);/* */
Sft_InitPicture(&CellInfo..CellPicture1);
Sft_SetPictureBitmap(&CellInfo..CellPicture1, m_CellBitmap);/* Assign bitmap */
m_Tree.SetCellInfo(&CellInfo); /* Register use of */
}
m_Tree.SetTreeLineStyle(SFTTREE_TREELINE_DOT);/* Dotted */
m_Tree.SetShowButtons(FALSE); /* Expand/collapse buttons (level 1..n) */
m_Tree.SetShowGrid(TRUE); /* Show grid */
m_Tree.SetGridStyle(SFTTREE_GRID_BOTH_DOT);/* Dotted */
m_Tree.SetShowTruncated(TRUE); /* Show ... if truncated */
m_Tree.SetNoFocusStyle(SFTTREE_NOFOCUS_FRAME);/* No focus, show frame */
m_Tree.SetSelectionStyle(SFTTREE_SELECTION_CELL1 | SFTTREE_SELECTION_OUTLINE);/* Select first only using outline */
m_Tree.SetSelectionArea(SFTTREE_SELECTIONAREA_ALL);/* Selection changes by clicking anywhere on an item */
m_Tree.SetFlyby(TRUE); /* Flyby highlighting */
m_Tree.SetCrossColumnResize(TRUE); /* Resize multiple columns */
m_Tree.SetReorderColumns(TRUE); /* Column reordering */
m_Tree.SetOpenEnded(TRUE); /* Last column width */
m_Tree.SetShowHeaderButtons(TRUE); /* Show column header as buttons */
/* Define columns */
{
SFTTREE_COLUMN_EX aCol[2] = {
{ 0, 0, /* Reserved */
100, /* Width (in pixels) */
ES_LEFT | SFTTREE_TOOLTIP, /* alignment */
ES_LEFT | SFTTREE_HEADER_UP, /* Title style */
_T("First Column"), /* Column header title */
NULL, NULL, /* Reserved field and bitmap handle */
SFTTREE_BMP_RIGHT, /* Picture alignment */
0, 0, 0, /* Reserved fields */
SFTTREE_NOCOLOR, /* background color */
SFTTREE_NOCOLOR, /* foreground color */
SFTTREE_NOCOLOR, /* Selected background color */
SFTTREE_NOCOLOR, /* Selected foreground color */
0, /* Real column position (set by SetColumns call) */
0, /* Display column number (display position) */
SFTTREE_COL_MERGE | /* Column can merge with next */
SFTTREE_COL_MERGEINTO | /* Previous column can merge into this column */
0, /* Column flag */
0, /* Minimum column width */
},
{ 0, 0, /* Reserved */
253, /* Width (in pixels) */
ES_LEFT | SFTTREE_TOOLTIP, /* alignment */
ES_LEFT | SFTTREE_HEADER_UP, /* Title style */
_T("Second Column"), /* Column header title */
NULL, NULL, /* Reserved field and bitmap handle */
SFTTREE_BMP_RIGHT, /* Picture alignment */
0, 0, 0, /* Reserved fields */
SFTTREE_NOCOLOR, /* background color */
SFTTREE_NOCOLOR, /* foreground color */
SFTTREE_NOCOLOR, /* Selected background color */
SFTTREE_NOCOLOR, /* Selected foreground color */
0, /* Real column position (set by SetColumns call) */
1, /* Display column number (display position) */
SFTTREE_COL_MERGE | /* Column can merge with next */
SFTTREE_COL_MERGEINTO | /* Previous column can merge into this column */
0, /* Column flag */
0, /* Minimum column width */
}
};
m_Tree.SetColumns(2, aCol); /* Set column attributes */
}
m_Tree.SetShowRowHeader(SFTTREE_ROWSTYLE_BUTTONCOUNT1);/* Row style */
m_Tree.SetRowColHeaderText(_T("?")); /* text */
m_Tree.SetRowColHeaderStyle(ES_LEFT | SFTTREE_HEADER_UP);/* style */
Sft_InitPicture(&Pic); /* Initialize */
Sft_SetPictureBitmap(&Pic, m_RowColBitmap);
m_Tree.SetRowColHeaderPicture(&Pic); /* Row/column picture */
m_Tree.SetRowColHeaderPictureStyle(SFTTREE_BMP_RIGHT);/* Row/column picture alignment */
m_Tree.SetDragBitmaps(TRUE); /* Allow drag & drop from item, */
m_Tree.SetDragType(SFTTREE_DRAG_PIXELIMM);/* Select and move by a number of pixels to start drag */
m_Tree.SetDropHighlightStyle(SFTTREE_DROPHIGHLIGHT_ONTOP);/* Highlight drop target */
/*------------------------------------------------------------------------------*/
/* Add a few items. */
/*------------------------------------------------------------------------------*/
int i, index;
index = m_Tree.AddString(_T("Items can be copied within this tree control.")); /* Add an item */
index = m_Tree.AddString(_T("Item text can be copied to other applications.")); /* Add an item */
index = m_Tree.AddString(_T("Files/folders can be dropped here (from Windows Explorer) and their names are added to the tree control.")); /* Add an item */
for (i = 0 ; i < 30 ; ) {
CString str;
str.Format(_T("Item %d"), i);
index = m_Tree.AddString(str); /* Add an item */
++i;
str.Format(_T("Item %d"), i);
index = m_Tree.AddString(str); /* Add another item */
m_Tree.SetText(index, 1, _T("2nd Column"));/* Set text in next column */
/* Set an item's row header text using: */
m_Tree.SetRowText(index, _T(">")); /* Row header text */
++i;
str.Format(_T("Item %d"), i);
index = m_Tree.AddString(str); /* Add another item */
m_Tree.SetText(index, 1, _T("2nd Column"));/* Set text in next column */
++i;
str.Format(_T("Item %d"), i);
index = m_Tree.AddString(str); /* Add another item */
m_Tree.SetText(index, 1, _T("2nd Column"));/* Set text in next column */
/* Set a */
SFTTREE_CELLINFOPARM CellInfo;
CellInfo.version = 7;
CellInfo.index = index;
CellInfo.iCol = 1;
m_Tree.GetCellInfo(&CellInfo);
Sft_SetPictureBitmap(&CellInfo..CellPicture1, m_CellBitmap);
m_Tree.SetCellInfo(&CellInfo);
++i;
}
/*------------------------------------------------------------------------------*/
/* Once ALL TREE CONTROL ITEMS HAVE BEEN ADDED, you can set additional tree */
/* control attributes. */
/*------------------------------------------------------------------------------*/
/* Make all column widths optimal, so text and bitmaps are */
/* not clipped horizontally. */
m_Tree.MakeColumnOptimal(-1, 0, FALSE);/* Make column widths optimal */
/* Make row header width optimal, so text and bitmaps are */
/* not clipped horizontally. */
m_Tree.MakeRowHeaderOptimal(0, FALSE);/* Make row header width optimal */
m_Tree.RecalcHorizontalExtent(0, FALSE);/* Update horizontal scroll bar */
// Register this tree control as a possible drop target
m_dropTarget.Register(&m_Tree);
return 0;
}
void CSampleView::OnSize(UINT nType, int cx, int cy)
{
CView::OnSize(nType, cx, cy);
m_Tree.MoveWindow(0, 0, cx, cy);
}
/* Respond to expand/collapse requests as the user clicks */
/* on different tree components. The events handled here */
/* can be changed to suit your application. */
void CSampleView::OnLButtonExpandCollapse()
{
/* get index of item to expand/collapse */
int index = m_Tree.GetExpandCollapseIndex();
/* get current expand/collapsed status */
BOOL fExpanded = m_Tree.GetItemExpand(index);
/* if control key is used we'll expand all */
BOOL fDepth = (::GetKeyState(VK_CONTROL)&0x8000);
if (fExpanded)
m_Tree.Collapse(index, TRUE);
else
m_Tree.Expand(index, TRUE, fDepth);
}
/* Respond to numeric keypad multiply key. */
void CSampleView::OnExpandAll()
{
/* get index of item to expand/collapse */
int index = m_Tree.GetExpandCollapseIndex();
m_Tree.Expand(index, TRUE, TRUE);
}
void CSampleView::OnLButtonDblClkColumnResize()
{
/* Resize column optimally */
int realCol = m_Tree.GetResizeColumn();
if (realCol >= 0) {
m_Tree.MakeColumnOptimal(realCol);/* Make column width optimal */
m_Tree.RecalcHorizontalExtent(0, FALSE);/* Update horizontal scroll bar */
}
}
// Drag & drop support
void CSampleView::OnBeginDrag()
{
/* Drag & drop started */
// determine what item is being dragged
int index = m_Tree.GetCaretIndex();
CString str;
m_Tree.GetText(index, 0, str);// get the item's text
// turn off the tree's built-in drag & drop, we'll use OLE drag & drop instead
m_Tree.SendMessage(WM_CANCELMODE);
// use CacheData or CacheGlobalData to define the data to be moved/copied
// In this example, the of the source item is copied into a global
// storage area
m_dataSource.Empty();
HGLOBAL hGlobal = ::GlobalAlloc(GHND, (str.GetLength()+1)*sizeof(TCHAR));
if (!hGlobal)
return;
LPTSTR lpStr = (LPTSTR) GlobalLock(hGlobal);
lstrcpy(lpStr, (LPCTSTR) str);// copy the into the global area
GlobalUnlock(hGlobal);
m_dataSource.CacheGlobalData(CF_TEXT, hGlobal);
// Initiate the OLE drag & drop, OLE mechanisms now take over (using COleDropSource
// and COleDataSource classes defined here) and COleDropTarget in the target control/window
m_dataSource.DoDragDrop( DROPEFFECT_COPY|DROPEFFECT_MOVE, NULL, &m_dropSource);
}
// The COleDropTarget class needs a little help so target highlighting works
// correctly. Anytime a drag&drop ends up above the tree control, the
// COleDropTarget class handles the events.
DROPEFFECT CTreeDropTarget::OnDragEnter( CWnd* pWnd, COleDataObject* pDataObject, DWORD dwKeyState, CPoint point )
{
if (!pWnd->IsKindOf(RUNTIME_CLASS(CSftTree)))
return DROPEFFECT_NONE;
CSftTree* pTree = (CSftTree*) pWnd;
// clear drop highlight
pTree->SetDropHighlight(-1);
return DROPEFFECT_NONE;
}
DROPEFFECT CTreeDropTarget::OnDragOver( CWnd* pWnd, COleDataObject* pDataObject, DWORD dwKeyState, CPoint point )
{
if (!pWnd->IsKindOf(RUNTIME_CLASS(CSftTree)))
return DROPEFFECT_NONE;
CSftTree* pTree = (CSftTree*) pWnd;
// find the index of the item at the cursor position
int index = pTree->CalcIndexFromPointEx(&point);
if (index < 0) {
pTree->SetDropHighlight(-1);
return DROPEFFECT_NONE;
}
// if the data being dragged into the control isn't in the proper format,
// dropping isn't possible
if (!pDataObject->IsDataAvailable(CF_TEXT) && !pDataObject->IsDataAvailable(CF_HDROP)
)
return DROPEFFECT_NONE;
// determine the desired "drop" effect
// DROPEFFECT_NONE The data object cannot be dropped in this window.
// DROPEFFECT_LINK for MK_CONTROL | MK_SHIFT Creates a linkage between the object and its server.
// not used in this example
// DROPEFFECT_COPY for MK_CONTROL Creates a copy of the dropped object.
// DROPEFFECT_MOVE for MK_ALT Creates a copy of the dropped object and delete the original object.
// This is typically the default drop effect, when the view can accept the data object.
// not used in this example (as it might be too destructive for illustration purposes)
DROPEFFECT effect = DROPEFFECT_COPY;
// set the item's drop highlight indicator (start scrolling if it's
// an item at the top or bottom of the control
pTree->SetDropHighlight(index, TRUE);
return effect;
}
void CTreeDropTarget::OnDragLeave( CWnd* pWnd )
{
if (!pWnd->IsKindOf(RUNTIME_CLASS(CSftTree)))
return;
CSftTree* pTree = (CSftTree*) pWnd;
// clear drop highlight
pTree->SetDropHighlight(-1);
return;
}
DROPEFFECT CTreeDropTarget::OnDropEx( CWnd* pWnd, COleDataObject* pDataObject, DROPEFFECT dropDefault, DROPEFFECT dropList, CPoint point )
{
if (!pWnd->IsKindOf(RUNTIME_CLASS(CSftTree)))
return DROPEFFECT_NONE;
CSftTree* pTree = (CSftTree*) pWnd;
// determine the drop-target item
int dropIndex = pTree->GetDropHighlight();
// make sure InsertString adds AFTER the drop-target
if (dropIndex >= 0)
++dropIndex;
// clear drop highlight
pTree->SetDropHighlight(-1);
// extract the data that arrived here. This is just a sample
// and is very application specific.
STGMEDIUM StgMedium;
CFile*pFile = pDataObject->GetFileData(CF_TEXT, NULL);
if (pFile) {
// the data is in CF_TEXT format, just add the text as a new item at
// the insertion point
TCHAR szBuffer[256];
pFile->Read(szBuffer, sizeof(szBuffer)/sizeof(TCHAR));
int index = pTree->InsertString(dropIndex, szBuffer);
pTree->SetCaretIndex(index);
pTree->SetCurSel(index);
++dropIndex;
delete pFile;
} else if (pDataObject->GetData(CF_HDROP, &StgMedium, NULL) && StgMedium.tymed == TYMED_HGLOBAL) {
// the data is in CF_HDROP format (a list of files from Windows Explorer),
// just add each new item at the insertion point
TCHAR szBuffer[_MAX_PATH];
int nFiles = DragQueryFile((HDROP)StgMedium.hGlobal, -1, NULL, 0); // get # of files
for (int i = 0 ; i < nFiles ; ++i) {
// extract one file
DragQueryFile((HDROP)StgMedium.hGlobal, i, szBuffer, sizeof(szBuffer)/sizeof(TCHAR)); // get file name
// insert it as a new item in the tree control
int index = pTree->InsertString(dropIndex, szBuffer);
pTree->SetCaretIndex(index);
pTree->SetCurSel(index);
++dropIndex;
}
}
return DROPEFFECT_COPY;
}
// The COleDropSource default implementation works just fine.
// The COleDropSource class can be used to control the
// drag & drop behaviour when the tree control is the
// origin of a drag & drop
SCODE CTreeDropSource::GiveFeedback(DROPEFFECT dropEffect)
{
return COleDropSource::GiveFeedback(dropEffect);
}
BOOL CTreeDropSource::OnBeginDrag(CWnd* pWnd)
{
return COleDropSource::OnBeginDrag(pWnd);
}
SCODE CTreeDropSource::QueryContinueDrag(BOOL bEscapePressed, DWORD dwKeyState)
{
return COleDropSource::QueryContinueDrag(bEscapePressed, dwKeyState);
}
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