How to Drag and Drop Ink in WPF

The following example creates an application that enables the user to drag selected strokes from one InkCanvas to the other.

XAML
<Window x:Class="Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="InkDragDropSample" Height="500" Width="700"
>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>

<InkCanvas Name="ic1" AllowDrop="True"
Grid.Column="0" Grid.Row="0"
Margin="10,10,10,10" Background="AliceBlue"
PreviewMouseDown="InkCanvas_PreviewMouseDown"
Drop="InkCanvas_Drop"/>

<InkCanvas Name="ic2" AllowDrop="True"
Grid.Column="1" Grid.Row="0"
Margin="10,10,10,10" Background="Beige"
PreviewMouseDown="InkCanvas_PreviewMouseDown"
Drop="InkCanvas_Drop"/>

<CheckBox Grid.Row="1"
Checked="switchToSelect" Unchecked="switchToInk">
Select Mode
</CheckBox>
</Grid>
</Window>
C#
using System;
using System.IO;
using System.Windows;
using System.Windows.Ink;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Input;
using System.Windows.Media;

public partial class Window1 : Window
{

public Window1()
{
InitializeComponent();
}

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);
}
}
}

void InkCanvas_Drop(object sender, DragEventArgs e)
{
// Get the strokes that were moved.
InkCanvas ic = (InkCanvas)sender;
MemoryStream ms = (MemoryStream)e.Data.GetData(
StrokeCollection.InkSerializedFormat);
ms.Position = 0;
StrokeCollection strokes = new StrokeCollection(ms);

// Translate the strokes to the position at which
// they were dropped.
Point pt = e.GetPosition(ic);
TranslateStrokes(strokes, pt.X, pt.Y);

// Add the strokes to the InkCanvas and keep them selected.
ic.Strokes.Add(strokes);
ic.Select(strokes);
}

// Helper method that transletes the specified strokes.
void TranslateStrokes(StrokeCollection strokes,
double x, double y)
{
Matrix mat = new Matrix();
mat.Translate(x, y);
strokes.Transform(mat, false);
}

void switchToSelect(object sender, RoutedEventArgs e)
{
ic1.EditingMode = InkCanvasEditingMode.Select;
ic2.EditingMode = InkCanvasEditingMode.Select;
}

void switchToInk(object sender, RoutedEventArgs e)
{
ic1.EditingMode = InkCanvasEditingMode.Ink;
ic2.EditingMode = InkCanvasEditingMode.Ink;
}
}