从ListBox中拖拽一个图片到Canvas上,然后在Canvas上

再次感谢楼上各位的回复,其实我想实现从ListBox中拖拽一个图片到Canvas上,然后在Canvas上对图片进行缩放、旋转等操作。

经过整理，基本实现了以上功能，但略有出入，且界面粗糙。现把代码贴出来与大家共享。

  <Window.Resources >
  <MatrixTransform x:Key="InitialMatrixTransform">
  <MatrixTransform.Matrix>
  <Matrix OffsetX="0" OffsetY="0"/>
  </MatrixTransform.Matrix>
  </MatrixTransform>
  </Window.Resources>
   
  <Grid>
  <Grid.ColumnDefinitions>
  <ColumnDefinition Width="210"></ColumnDefinition>
  <ColumnDefinition></ColumnDefinition>
  </Grid.ColumnDefinitions>
   
  <ListView PreviewMouseLeftButtonDown="StackPanel_PreviewMouseLeftButtonDown" 
  Grid.Column="0" Foreground="Gold" AllowDrop="True" x:Name="lstParent" 
  PreviewMouseMove="StackPanel_PreviewMouseMove" Margin="5,0,0,0"
  ScrollViewer.VerticalScrollBarVisibility="Hidden" 
  ScrollViewer.HorizontalScrollBarVisibility="Hidden">
  <ListViewItem Height="150">
  <Image Source="Resources\Images\a01.jpg"></Image>
  </ListViewItem>
  <ListViewItem Height="150">
  <Image Source="Resources\Images\a02.jpg"></Image>
  </ListViewItem>
  <ListViewItem Height="150">
  <Image Source="Resources\Images\a03.jpg"></Image>
  </ListViewItem>
  <ListViewItem Height="150">
  <Image Source="Resources\Images\a04.jpg"></Image>
  </ListViewItem>
  </ListView>
  <Canvas x:Name="canvas" Grid.Column="1" AllowDrop="True"
  Drop="Canvas_Drop" DragEnter="Canvas_DragEnter" 
  Width="Auto" Height="Auto" Background="WhiteSmoke"
  RenderTransform="{StaticResource InitialMatrixTransform}" 
  IsManipulationEnabled="True" 
  ManipulationStarting="canvas_ManipulationStarting" 
  ManipulationInertiaStarting="canvas_ManipulationInertiaStarting" 
  ManipulationDelta="canvas_ManipulationDelta">
  </Canvas>
  </Grid>



  Point startPoint;
  ListBoxItem contact;

  public Window4()
  {
  InitializeComponent();
  }

  private void StackPanel_Click(object sender, RoutedEventArgs e)
  {
  MessageBox.Show("Routed Event");
  }

  private void Canvas_Drop(object sender, DragEventArgs e)
  {
  if (e.Data.GetDataPresent("MyFormat"))
  {
  contact = e.Data.GetData("MyFormat") as ListBoxItem;
  Canvas CanvasView = sender as Canvas;
  this.lstParent.Items.Remove(contact);
  CanvasView.Children.Add(contact);
  }
  }

  private void Canvas_DragEnter(object sender, DragEventArgs e)
  {
  if (!(e.Data.GetDataPresent("contact")) || (sender == e.Source))
  {
  e.Effects = DragDropEffects.None;
  }
  }

  private void StackPanel_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
  {
  startPoint = e.GetPosition(null);
  }

  private void StackPanel_PreviewMouseMove(object sender, MouseEventArgs e)
  {
  Point mousPos = e.GetPosition(null);
  Vector diff = startPoint - mousPos;

  if ((e.LeftButton == MouseButtonState.Pressed) && (Math.Abs(diff.X) > SystemParameters.MinimumHorizontalDragDistance) && (Math.Abs(diff.Y) > SystemParameters.MinimumVerticalDragDistance))
  {
  ListView listView = sender as ListView;
  ListViewItem listViewItem = FindAnchestor<ListViewItem>((DependencyObject)e.OriginalSource);
  if (listViewItem == null) { return; }
  contact = (ListViewItem)listView.ItemContainerGenerator.ItemFromContainer(listViewItem);
  DataObject dataObject = new DataObject("MyFormat", contact);
  DragDrop.DoDragDrop(listViewItem, dataObject, DragDropEffects.Move);
  }
  }
  private static T FindAnchestor<T>(DependencyObject current) where T : DependencyObject
  {
  do
  {
  if (current is T)
  {
  return (T)current;
  }
  current = VisualTreeHelper.GetParent(current);
  }
  while (current != null);

  return null;
  }

  private void canvas_ManipulationStarting(object sender, ManipulationStartingEventArgs e)
  {
  e.ManipulationContainer = this.canvas;
  e.Handled = true;
  }

  private void canvas_ManipulationInertiaStarting(object sender, ManipulationInertiaStartingEventArgs e)
  {
  // Decrease the velocity of the Rectangle's movement by 
  // 10 inches per second every second.
  // (10 inches * 96 DIPS per inch / 1000ms^2)
  e.TranslationBehavior = new InertiaTranslationBehavior()
  {
  InitialVelocity = e.InitialVelocities.LinearVelocity,
  DesiredDeceleration = 10.0 * 96.0 / (1000.0 * 1000.0)
  };

  // Decrease the velocity of the Rectangle's resizing by 
  // 0.1 inches per second every second.
  // (0.1 inches * 96 DIPS per inch / (1000ms^2)
  e.ExpansionBehavior = new InertiaExpansionBehavior()
  {
  InitialVelocity = e.InitialVelocities.ExpansionVelocity,
  DesiredDeceleration = 0.1 * 96 / 1000.0 * 1000.0
  };

  // Decrease the velocity of the Rectangle's rotation rate by 
  // 2 rotations per second every second.
  // (2 * 360 degrees / (1000ms^2)
  e.RotationBehavior = new InertiaRotationBehavior()
  {
  InitialVelocity = e.InitialVelocities.AngularVelocity,
  DesiredDeceleration = 720 / (1000.0 * 1000.0)
  };
  e.Handled = true;
  }

  private void canvas_ManipulationDelta(object sender, ManipulationDeltaEventArgs e)
  {
  //this just gets the source. 
  // I cast it to FE because I wanted to use ActualWidth for Center. You could try RenderSize as alternate
  var element = e.Source as FrameworkElement;
  if (element != null)
  {
  //e.DeltaManipulation has the changes 
  // Scale is a delta multiplier; 1.0 is last size, (so 1.1 == scale 10%, 0.8 = shrink 20%) 
  // Rotate = Rotation, in degrees
  // Pan = Translation, == Translate offset, in Device Independent Pixels 

  var deltaManipulation = e.DeltaManipulation;
  var matrix = ((MatrixTransform)element.RenderTransform).Matrix;
  // find the old center; arguaby this could be cached 
  Point center = new Point(element.ActualWidth / 2, element.ActualHeight / 2);
  // transform it to take into account transforms from previous manipulations 
  center = matrix.Transform(center);
  //this will be a Zoom. 
  matrix.ScaleAt(deltaManipulation.Scale.X, deltaManipulation.Scale.Y, center.X, center.Y);
  // Rotation 
  matrix.RotateAt(e.DeltaManipulation.Rotation, center.X, center.Y);
  //Translation (pan) 
  matrix.Translate(e.DeltaManipulation.Translation.X, e.DeltaManipulation.Translation.Y);

  ((MatrixTransform)element.RenderTransform).Matrix = matrix;

  e.Handled = true;
  }
  }