WPF实现抽屉效果

界面代码（xaml）：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace TransAnimation
{
    /// 

    /// MainWindow.xaml 的交互逻辑
    /// 
    public partial class MainWindow : Window
    {
        
        private bool _Expand = true;

        public MainWindow()
        {
            InitializeComponent();
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            Expand = !_Expand;
        }

        
        public bool Expand
        {
            get { return _Expand; }
            set
            {
                _Expand = value;

                Duration duration = new Duration(TimeSpan.FromSeconds(2));
                FillBehavior behavior = FillBehavior.HoldEnd;

                DoubleAnimation translateAnim = new DoubleAnimation();
                translateAnim.Duration = duration;
                translateAnim.FillBehavior = behavior;

                RectAnimation clipAnim = new RectAnimation();
                clipAnim.Duration = duration;
                clipAnim.FillBehavior = behavior;

                double delta = 40; //收缩的大小

                if (_Expand) // Expand
                {
                    translateAnim.From = -delta;
                    translateAnim.To = 0;

                    clipAnim.From = new Rect(delta, 0, Thumb1.ActualWidth, Thumb1.ActualHeight);
                    clipAnim.To = new Rect(0, 0, Thumb1.ActualWidth, Thumb1.ActualHeight);
                }
                else  //Shrink
                {
                    translateAnim.From = 0;
                    translateAnim.To = -delta;

                    clipAnim.From = new Rect(0, 0, Thumb1.ActualWidth, Thumb1.ActualHeight);
                    clipAnim.To = new Rect(delta, 0, Thumb1.ActualWidth, Thumb1.ActualHeight);
                }

                spt1.BeginAnimation(TranslateTransform.XProperty, translateAnim);
                spc1.BeginAnimation(RectangleGeometry.RectProperty, clipAnim);
            }
        }

    }
}