static DragImage()
{
try
{
Helper = new DragDropHelper() as IDropTargetHelper;
}
catch (COMException)
{
}
}
public static bool GetIDropTargetHelper(out IntPtr helperPtr, out IDropTargetHelper dropHelper)
{
if (ShellAPI.CoCreateInstance(
ref ShellAPI.CLSID_DragDropHelper,
IntPtr.Zero,
ShellAPI.CLSCTX.INPROC_SERVER,
ref ShellAPI.IID_IDropTargetHelper,
out helperPtr) == ShellAPI.S_OK)
{
dropHelper =
(IDropTargetHelper)Marshal.GetTypedObjectForIUnknown(helperPtr, typeof(IDropTargetHelper));
return true;
}
else
{
dropHelper = null;
helperPtr = IntPtr.Zero;
return false;
}
}
private void dataGridView1_DragLeave(object sender, EventArgs e)
{
IDropTargetHelper dropHelper = (IDropTargetHelper) new DragDropHelper();
dropHelper.DragLeave();
}
public static bool GetIDropTargetHelper(out IntPtr helperPtr, out IDropTargetHelper dropHelper)
{
if (Ole32.CoCreateInstance(ref ShellGuids.DragDropHelper, IntPtr.Zero, CLSCTX.InProcServer, ref ShellGuids.IDropTargetHelper, out helperPtr) == 0)
{
dropHelper = (IDropTargetHelper)Marshal.GetTypedObjectForIUnknown(helperPtr, typeof(IDropTargetHelper));
return true;
}
else
{
dropHelper = null;
helperPtr = IntPtr.Zero;
return false;
}
}
/// <summary>
/// Notifies the DragDropHelper that the current Window received
/// a Drop event.
/// </summary>
/// <param name="dropHelper">The DragDropHelper instance to notify.</param>
/// <param name="data">The DataObject containing a drag image.</param>
/// <param name="cursorOffset">The current cursor's offset relative to the window.</param>
/// <param name="effect">The accepted drag drop effect.</param>
public static void Drop(this IDropTargetHelper dropHelper, System.Windows.IDataObject data, Point cursorOffset, DragDropEffects effect)
{
Win32Point pt = cursorOffset.ToWin32Point();
dropHelper.Drop((IDataObject)data, ref pt, (int)effect);
}
/// <summary>
/// Notifies the DragDropHelper that the current Window received
/// a DragOver event.
/// </summary>
/// <param name="dropHelper">The DragDropHelper instance to notify.</param>
/// <param name="cursorOffset">The current cursor's offset relative to the window.</param>
/// <param name="effect">The accepted drag drop effect.</param>
public static void DragOver(this IDropTargetHelper dropHelper, Point cursorOffset, DragDropEffects effect)
{
Win32Point pt = cursorOffset.ToWin32Point();
dropHelper.DragOver(ref pt, (int)effect);
}
// ----------------------------------------------------------------------------------------------
#region Impelmentation
/// <summary>
/// Create or handle a system-style Drag & Drop icon
/// </summary>
/// <param name="element">Element to represent or where the Drag & Drop operation occurs</param>
/// <param name="dataObject">Data Object dragged during Drag & Drop</param>
/// <param name="effects">Drag & Drop effects</param>
/// <param name="scale">Scale of the element representation when creating icon (1.0: unchanged)</param>
/// <param name="create">create the icon representation from the element, otherwise tries to continue the existing Drag & Drop from the dataObject</param>
public DragSystemIcon(FrameworkElement element, IDataObject dataObject, DragDropEffects effects, double scale, bool create)
{
// retrieve window handle
var window = PresentationSource.FromVisual(element).RootVisual;
var hwnd = ((HwndSource)PresentationSource.FromVisual(window)).Handle;
if (create)
{
Element = element;
if (element is ContentPresenter)
{
element = WPF.FindFirstChild <FrameworkElement>(element);
}
// Convert the visual element to a Bitmap
var dpi = 96 * scale;
var renderbmp = WPF.ProduceImageSourceForVisual(element, dpi, dpi);
// Retrieve renderbmp pixel array
const int pixsize = 4; // Pbgra32 implies 4 bytes per pixels
int stride = renderbmp.PixelWidth * pixsize;
byte[] pix = new byte[renderbmp.PixelHeight * stride];
renderbmp.CopyPixels(pix, stride, 0);
for (int i = 3; i < pix.Length; i += pixsize)
{
if (pix[i] == 0)
{
// Convert fully transparent pixels to Magenta (this will become transparent in ShDragImage)
pix[i - 0] = 0xFF; // A
pix[i - 1] = 0xFF; // R
pix[i - 2] = 0x00; // G
pix[i - 3] = 0xFF; // B
}
else if (pix[i] == 0xFF && pix[i - 1] == 0xFF && pix[i - 2] == 0x00 && pix[i - 3] == 0xFF)
{
// change Magenta pixels to *almost* magenta, to avoid changing these to transparent in ShDragImage
pix[i - 2] = 0x01;
}
}
// Convert pixel array to BitmapSource
var bitmapsrc = BitmapSource.Create(renderbmp.PixelWidth, renderbmp.PixelHeight,
96, 96, PixelFormats.Bgra32, null, pix, stride);
// Convert BitmapSource to Bitmap
System.Drawing.Bitmap bitmap;
using (System.IO.MemoryStream stream = new System.IO.MemoryStream())
{
var encoder = new BmpBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bitmapsrc));
encoder.Save(stream);
bitmap = new System.Drawing.Bitmap(stream);
}
//LimeMsg.Debug("ClipDragDrop DragSystemIcon: {0}", bitmap.GetPixel(0, 0));
// Compute destination size
WPF.Win32Size size;
size.cx = (int)(renderbmp.PixelWidth * scale);
size.cy = (int)(renderbmp.PixelHeight * scale);
WPF.SysPoint wpt;
wpt.x = size.cx / 2;
wpt.y = size.cy / 2;
ShDragImage shdi = new ShDragImage
{
sizeDragImage = size,
ptOffset = wpt,
hbmpDragImage = bitmap.GetHbitmap(),
crColorKey = System.Drawing.Color.Magenta.ToArgb()
};
var sourceHelper = (IDragSourceHelper2) new DragDropHelper();
sourceHelper.SetFlags(1); // Enable Drop description
// Not quite right
var com = new ComDataObject();
dataObject = new DataObject(com);
sourceHelper.InitializeFromBitmap(ref shdi, (System.Runtime.InteropServices.ComTypes.IDataObject)dataObject);
}
else
{
Element = null;
}
ComData = dataObject;
Effects = effects;
Scale = scale;
// Create the System Drag Helper and show it at the mouse location
WPF.GetCursorPos(out WPF.SysPoint spos);
DDHelper = (IDropTargetHelper) new DragDropHelper();
DDHelper.DragEnter(hwnd,
(System.Runtime.InteropServices.ComTypes.IDataObject)dataObject,
ref spos, Effects);
}
