/// <summary>
/// Update the displayed drag drop effects
/// </summary>
/// <param name="effects">Drag & Drop effect to be applied</param>
/// <param name="type">DropImageType effect to be used</param>
/// <param name="format">format to be displayed on the icon</param>
/// <param name="destination">drop destination name</param>
public void UpdateEffects(DragDropEffects effects, DropImageType type, string format, string destination)
{
Effects = effects;
if (ComData != null)
{
// Size of insert is limited to 259
if (destination != null && destination.Length > 259)
{
destination = destination.Substring(255) + "...";
}
// C# format to C format
format = format?.Replace("{0}", "%1");
// All these steps are required to update the Drop-description
ComDataObject.SetDropDescription(ComData, type, format, destination);
ComDataObject.InvalidateDragImage(ComData);
UpdatePosition(); // force a DDHelper.DragOver call
}
}
/// <summary>
/// Gets managed data from a clipboard DataObject.
/// </summary>
/// <param name="dataObject">The DataObject to obtain the data from.</param>
/// <param name="format">The format for which to get the data in.</param>
/// <returns>The data object instance.</returns>
public static object GetManagedData(ComDataObject dataObject, string format)
{
FillFormatETC(format, TYMED.TYMED_HGLOBAL, out FORMATETC formatETC);
// Get the data as a stream
dataObject.GetData(ref formatETC, out STGMEDIUM medium);
IStream nativeStream;
try
{
int hr = CreateStreamOnHGlobal(medium.unionmember, true, out nativeStream);
if (hr != 0)
{
return(null);
}
}
finally
{
ReleaseStgMedium(ref medium);
}
// Convert the native stream to a managed stream
nativeStream.Stat(out System.Runtime.InteropServices.ComTypes.STATSTG statstg, 0);
if (statstg.cbSize > int.MaxValue)
{
throw new NotSupportedException();
}
byte[] buf = new byte[statstg.cbSize];
nativeStream.Read(buf, (int)statstg.cbSize, IntPtr.Zero);
MemoryStream dataStream = new MemoryStream(buf);
// Check for our stamp
int sizeOfGuid = Marshal.SizeOf(typeof(Guid));
byte[] guidBytes = new byte[sizeOfGuid];
if (dataStream.Length >= sizeOfGuid)
{
if (sizeOfGuid == dataStream.Read(guidBytes, 0, sizeOfGuid))
{
Guid guid = new Guid(guidBytes);
if (ManagedDataStamp.Equals(guid))
{
// Stamp matched, so deserialize
BinaryFormatter formatter = new BinaryFormatter();
Type dataType = (Type)formatter.Deserialize(dataStream);
object data2 = formatter.Deserialize(dataStream);
if (data2.GetType() == dataType)
{
return(data2);
}
else if (data2 is string)
{
return(ConvertDataFromString((string)data2, dataType));
}
else
{
return(null);
}
}
}
}
// Stamp didn't match... attempt to reset the seek pointer
if (dataStream.CanSeek)
{
dataStream.Position = 0;
}
return(null);
}
// ----------------------------------------------------------------------------------------------
#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);
}