private void HandleDragDelta(object sender, DragContainerEventArgs e)
{
// Don't actually start the drag unless the mouse has moved for enough away
// from the initial MouseDown point.
Point currentPoint = e.CurrentPosition;
if (Math.Abs(currentPoint.X - dragStartPoint.X) > SystemParameters.MinimumHorizontalDragDistance ||
Math.Abs(currentPoint.Y - dragStartPoint.Y) > SystemParameters.MinimumVerticalDragDistance)
{
this.isMouseDown = false;
// Since we have to have the data before the drag starts, we don't allow a drag for data that
// is not cached to avoid blocking the UI while the data is fetched before the drag starts.
if (IsDataAvailable())
{
IsInDrag = true;
int width = (int)this.RenderSize.Width;
int height = (int)this.RenderSize.Height;
RenderTargetBitmap rtb = new RenderTargetBitmap(width, height, 96.0, 96.0, PixelFormats.Pbgra32); // TODO: use actual dpi.
rtb.Render(this);
ConstrainSize(ref width, ref height, 200);
BitmapSource ghostImage = ResizeImage(rtb, width, height);
this.CaptureMouse();
Point mousePoint = new Point(0.5 * width, 0.5 * height);
#if USE_STANDARD_DRAGDROP
var dataObject = new System.Windows.DataObject();
var items = GetData();
foreach (var item in items)
{
dataObject.SetData(item.Key, item.Value);
}
DragDrop.DoDragDrop(this, dataObject, DragDropEffects.Copy);
#else
try
{
DragSourceHelper.DoDragDrop(this, ghostImage, mousePoint, DragDropEffects.Copy, GetData());
}
catch (COMException)
{
// DragDropLib is buggy. Fail silently if this happens.
}
#endif
this.ReleaseMouseCapture();
IsInDrag = false;
}
}
}
private void HandleDragCompleted(object sender, DragContainerEventArgs e)
{
this.isMouseDown = false;
}
private void HandleDragStarted(object sender, DragContainerEventArgs e)
{
this.dragStartPoint = e.InitialPosition;
this.isMouseDown = true;
}