我正在做一个Wpf应用程序，我创建了一个眼睛形状的控件，我在画布中放置了一个椭圆（眼睛），我的目的是当鼠标光标进入画布时，椭圆跟随鼠标光标。 您对如何执行此任务有什么建议吗？ 非常感谢您的关注。

Cheers

EDIT

我已经更新了 Xaml 中的代码：

<Window Height="480" Title="Window2" Width="640" x:Class="WpfApplication5.Window2"
   x:Name="Window" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Window.Resources>
    <Storyboard x:Key="OnLoaded1">
      <DoubleAnimationUsingKeyFrames Storyboard.TargetName="ctrCircle" 
        Storyboard.TargetProperty="(UIElement.RenderTransform).( TransformGroup.Children)[3].(TranslateTransform.X)">
        <EasingDoubleKeyFrame KeyTime="0:0:0.8" Value="1">
          <EasingDoubleKeyFrame.EasingFunction>
            <ExponentialEase EasingMode="EaseOut" />
          </EasingDoubleKeyFrame.EasingFunction>
      </EasingDoubleKeyFrame>
      </DoubleAnimationUsingKeyFrames>
      <DoubleAnimationUsingKeyFrames Storyboard.TargetName="ctrCircle" 
          Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(TranslateTransform.Y)">
        <EasingDoubleKeyFrame KeyTime="0:0:0.8" Value="1">
        <EasingDoubleKeyFrame.EasingFunction>
            <ExponentialEase EasingMode="EaseOut" />
          </EasingDoubleKeyFrame.EasingFunction>
        </EasingDoubleKeyFrame>
      </DoubleAnimationUsingKeyFrames>
    </Storyboard>
    <Style TargetType="Ellipse">
      <Setter Property="RenderTransform">
        <Setter.Value>
          <ScaleTransform ScaleX="1" ScaleY="1"/>
        </Setter.Value>
      </Setter>
      <Setter Property="RenderTransformOrigin" Value="0.5,0.5"/>
    </Style>
  </Window.Resources>

  <Canvas MouseMove="mov" x:Name="LayoutRoot">
    <Border ackground="Black" B="" Canvas.Left="178" Canvas.Top="103" 
      CornerRadius="250" Height="255.5" Width="290" x:Name="border_eye">
      <Ellipse Fill="#FFFFC600" Height="12" HorizontalAlignment="Left" 
        Margin="0" RenderTransformOrigin="0.5,0.5" Stroke="{x:Null}" 
        VerticalAlignment="Center" Visibility="Visible" Width="12" x:Name="ctrCircle">
        <Ellipse.RenderTransform>
          <TransformGroup>
            <ScaleTransform />
            <SkewTransform />
            <RotateTransform />
            <TranslateTransform />                 
          </TransformGroup>
        </Ellipse.RenderTransform>
      </Ellipse>
    </Border>
  </Canvas>
</Window>

并在后面的代码中：

private void mov(object sender, MouseEventArgs e)
    {
 System.Windows.Point pt = e.GetPosition((Canvas)sender);
      Storyboard invokeStoryboard = this.Resources["OnLoaded1"] as Storyboard;
        ((DoubleAnimationUsingKeyFrames)invokeStoryboard.Children[0]).KeyFrames[0].Value = pt.X;
        ((DoubleAnimationUsingKeyFrames)invokeStoryboard.Children[1]).KeyFrames[0].Value = pt.Y;
        invokeStoryboard.Begin();
    }

现在我的目的是，当我在画布区域（LayoutRoot）中移动鼠标时，椭圆（ctrCircle）仅在边框（border_eye）内移动，并且不克服“border_eye”的区域，这种效果类似于眼睛。

您有任何意见来完成此步骤吗？

非常感谢

祝你今天过得愉快。

Cheers

以下是如何使用 WPF 画布中的眼睛的示例接收框架 http://msdn.microsoft.com/en-us/devlabs/ee794896.aspx。使用 Rx 而不是直接附加到鼠标移动事件，您可以缓冲事件并仅每 10 毫秒更新一次瞳孔位置，从而减少总体 CPU 负载。

The Xaml

<UserControl
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    x:Class="namespace.EyeDemo"
    x:Name="UserControl"
    d:DesignWidth="640" d:DesignHeight="480">

    <Canvas x:Name="LayoutRoot" Background="GreenYellow">
        <Ellipse Fill="Black" Width="120" Height="70" Canvas.Left="90" Canvas.Top="115"/>
        <Ellipse x:Name="Eye" Fill="Black" Width="100" Height="50" Canvas.Left="100" Canvas.Top="125"/>
        <Ellipse x:Name="Pupil" Fill="Red" Height="20" Canvas.Left="139" Canvas.Top="138" Width="20"/>
    </Canvas>
</UserControl>

以及后面的代码

/// <summary>
/// Interaction logic for EyeDemo.xaml
/// </summary>
public partial class EyeDemo : UserControl
{
    public EyeDemo()
    {
        this.InitializeComponent();

        double majorRadius = Eye.Width / 2d;
        double minorRadius = Eye.Height / 2d;
        Point center = new Point( Canvas.GetLeft( Eye ) + majorRadius, Canvas.GetTop( Eye ) + minorRadius );

        // create event streams for mouse down/up/move using reflection
        // to keep taking mouse move events and return the X, Y positions
        var mouseMove = from evt in Observable.FromEvent<MouseEventArgs>( LayoutRoot, "PreviewMouseMove" )
                        select (Point?)evt.EventArgs.GetPosition( this );

        // subscribe to the stream of position changes and modify the Canvas.Left and Canvas.Top
        // use the bound by elipse function to restrain the pupil to with the eye.
        mouseMove.BufferWithTime( TimeSpan.FromMilliseconds( 10 ) ).Select( p => BoundByElipse( majorRadius, minorRadius, center, p.LastOrDefault() ) )
            .ObserveOnDispatcher().Subscribe( pos =>
              {
                  if( pos.HasValue )
                  {
                      Canvas.SetLeft( Pupil, pos.Value.X - Pupil.Width / 2d );
                      Canvas.SetTop( Pupil, pos.Value.Y - Pupil.Height / 2d );
                  }
              } );
    }

    private Point? BoundByElipse( double majorRadius, double minorRadius, Point center, Point? point )
    {
        if( point.HasValue )
        {
            // Formular for an elipse is  x^2 / a^2 + y^2 / b^2 = 1
            // where a = majorRadius and b = minorRadius
            // Using this formular we can work out if the point is with in the elipse 
            // or find the boundry point closest to the point

            // Find the location of the point relative to the center.
            Point p = new Point( point.Value.X - center.X, point.Value.Y - center.Y );
            double a = majorRadius;
            double b = minorRadius;

            double f = p.X * p.X / (a * a) + p.Y * p.Y / (b * b);
            if( f <= 1 )
            {
                // the point is with in the elipse;
                return point;
            }
            else
            {
                // the point is outside the elipse, therefore need to find the closest location on the boundry.
                double xdirection = point.Value.X > center.X ? 1 : -1;
                double ydirection = point.Value.X > center.X ? 1 : -1;

                double r = p.X / p.Y;

                double x = p.Y != 0 ? Math.Sqrt( r * r * a * a * b * b / (r * r * b * b + a * a) ) : a;
                double y = r != 0 ? x / r : (point.Value.Y > center.Y ? -b : b);

                return new Point( center.X + xdirection * x, center.Y + ydirection * y );
            }
        }
        else
        {
            return null;
        }
    }
}