public void OnInkCanvasPreviewMouseDown(object sender, MouseEventArgs e)
{
if (e == null)
{
return;
}
// Finger
if (e.StylusDevice != null && e.StylusDevice.StylusButtons.Count == 1 && !this.fingerSelectionMode)
{
this.InkCanvas.EditingMode = InkCanvasEditingMode.GestureOnly;
return;
}
// Stylus
if (e.StylusDevice != null && e.StylusDevice.StylusButtons.Count == 2)
{
return;
}
this.InkCanvas.EditingMode = InkCanvasEditingMode.Select;
InkCanvas ic = (InkCanvas)sender;
Point pt = e.GetPosition(ic);
if (ic.HitTestSelection(pt) == InkCanvasSelectionHitResult.Selection)
{
this.strokesToMove = ic.GetSelectedStrokes();
this.dragDropInProgress = true;
this.initialDragPoint = pt;
this.polledMouseCoords = new Point(pt.X, pt.Y);
}
}
//<Snippet3>
void InkCanvas_PreviewMouseDown(object sender, MouseEventArgs e)
{
InkCanvas ic = (InkCanvas)sender;
Point pt = e.GetPosition(ic);
// If the user is moving selected strokes, prepare the strokes to be
// moved to another InkCanvas.
if (ic.HitTestSelection(pt) ==
InkCanvasSelectionHitResult.Selection)
{
StrokeCollection selectedStrokes = ic.GetSelectedStrokes();
StrokeCollection strokesToMove = selectedStrokes.Clone();
// Remove the offset of the selected strokes so they
// are positioned when the strokes are dropped.
Rect inkBounds = strokesToMove.GetBounds();
TranslateStrokes(strokesToMove, -inkBounds.X, -inkBounds.Y);
// Perform drag and drop.
MemoryStream ms = new MemoryStream();
strokesToMove.Save(ms);
DataObject dataObject = new DataObject(
StrokeCollection.InkSerializedFormat, ms);
DragDropEffects effects =
DragDrop.DoDragDrop(ic, dataObject,
DragDropEffects.Move);
if ((effects & DragDropEffects.Move) ==
DragDropEffects.Move)
{
// Remove the selected strokes
// from the current InkCanvas.
ic.Strokes.Remove(selectedStrokes);
}
}
}
/// <summary>
/// OnPreviewMouseDown is called before InkCanvas sees the Down. We use this
/// handler to hit test any selection and initiate a drag and drop operation
/// if the user clicks on the selection to move it.
/// </summary>
private void OnPreviewMouseDown(object sender, MouseButtonEventArgs e)
{
InkCanvas inkCanvas = (InkCanvas)sender;
Point downPosition = e.GetPosition(inkCanvas);
//see if we hit the selection, and not a grab handle
if (inkCanvas.HitTestSelection(downPosition) == InkCanvasSelectionHitResult.Selection)
{
//clone the selected strokes so we can transform them without affecting the actual selection
StrokeCollection selectedStrokes = inkCanvas.GetSelectedStrokes();
List <UIElement> selectedElements = new List <UIElement>(inkCanvas.GetSelectedElements());
DataObject dataObject = new DataObject();
//copy ink to the clipboard if we have any. we do this even if there are no
//strokes since clonedStrokes will be used by the Xaml clipboard code below
StrokeCollection clonedStrokes = selectedStrokes.Clone();
if (clonedStrokes.Count > 0)
{
//translate the strokes relative to the down position
Matrix translation = new Matrix();
translation.Translate(-downPosition.X, -downPosition.Y);
clonedStrokes.Transform(translation, false);
//save the strokes to a dataobject to use during the dragdrop operation
MemoryStream ms = new MemoryStream();
clonedStrokes.Save(ms);
ms.Position = 0;
dataObject.SetData(StrokeCollection.InkSerializedFormat, ms);
//we don't close the MemoryStream here, we'll do it in OnDrop
}
//Now we're going to add Xaml to the dragdrop dataobject. We'll create an
//InkCanvas and add any selected strokes and elements in the selection to it
InkCanvas inkCanvasForDragDrop = new InkCanvas();
foreach (UIElement childElement in selectedElements)
{
//we can't add elements in the selection to the InkCanvas that
//represents selection (since they are already parented to the
//inkCanvas that has the selection) so we need to clone them.
//To clone each element, we need to convert it to Xaml and back again
string childXaml = XamlWriter.Save(childElement);
UIElement clonedChildElement =
(UIElement)XamlReader.Load(new XmlTextReader(new StringReader(childXaml)));
//adjust top and left relative to the down position
double childLeft = InkCanvas.GetLeft(clonedChildElement);
InkCanvas.SetLeft(clonedChildElement, childLeft - downPosition.X);
double childTop = InkCanvas.GetTop(clonedChildElement);
InkCanvas.SetTop(clonedChildElement, childTop - downPosition.Y);
inkCanvasForDragDrop.Children.Add(clonedChildElement);
}
//last, add the cloned strokes in case our drop location only supports Xaml
//this preserves both the ink and the selected elements
inkCanvasForDragDrop.Strokes = clonedStrokes;
//now copy the Xaml for the InkCanvas that represents selection to the clipboard
string inkCanvasXaml = XamlWriter.Save(inkCanvasForDragDrop);
dataObject.SetData(DataFormats.Xaml, inkCanvasXaml);
//The call to DragDrop.DoDragDrop will block until the drag and drop operation is completed
//once it does, 'effects' will have been updated by OnDragOver getting called
//if we're moving the strokes and elements, we'll remove them. If we're copying them
//(the CTRL key is pressed) we won't remove them.
DragDropEffects effects =
DragDrop.DoDragDrop(inkCanvas, dataObject, DragDropEffects.Move | DragDropEffects.Copy);
if (effects == DragDropEffects.Move)
{
inkCanvas.Strokes.Remove(selectedStrokes);
foreach (UIElement childElement in selectedElements)
{
inkCanvas.Children.Remove(childElement);
}
}
}
}
