WPF实现的加载动画

     <Grid x:Name="LayoutRoot" Background="Transparent"         ToolTip="Searching...."         HorizontalAlignment="Center"         VerticalAlignment="Center">             <Canvas RenderTransformOrigin="0.5,0.5"             HorizontalAlignment="Center"             VerticalAlignment="Center" Width="120"             Height="120" Loaded="HandleLoaded"             Unloaded="HandleUnloaded"  >                 <Ellipse x:Name="C0" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="1.0"/>                 <Ellipse x:Name="C1" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="0.9"/>                 <Ellipse x:Name="C2" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="0.8"/>                 <Ellipse x:Name="C3" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="0.7"/>                 <Ellipse x:Name="C4" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="0.6"/>                 <Ellipse x:Name="C5" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="0.5"/>                 <Ellipse x:Name="C6" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="0.4"/>                 <Ellipse x:Name="C7" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="0.3"/>                 <Ellipse x:Name="C8" Width="20" Height="20"                     Canvas.Left="0"                     Canvas.Top="0" Stretch="Fill"                     Fill="#bbc3de" Opacity="0.2"/>                 <Canvas.RenderTransform>                     <RotateTransform x:Name="SpinnerRotate"                     Angle="0" />                 </Canvas.RenderTransform>             </Canvas>         </Grid> 

 public partial class UserControlLoad : UserControl     {         public UserControlLoad()         {             InitializeComponent();             animationTimer = new DispatcherTimer( DispatcherPriority.ContextIdle, Dispatcher);             animationTimer.Interval = new TimeSpan(0, 0, 0, 0, 75);             Start();         }         private readonly DispatcherTimer animationTimer;         #region Private Methods         public void Start()         {             Mouse.OverrideCursor = Cursors.Wait;             animationTimer.Tick += HandleAnimationTick;             animationTimer.Start();         }          private void Stop()         {             animationTimer.Stop();             Mouse.OverrideCursor = Cursors.Arrow;             animationTimer.Tick -= HandleAnimationTick;         }          private void HandleAnimationTick(object sender, EventArgs e)         {             SpinnerRotate.Angle = (SpinnerRotate.Angle + 36) % 360;         }          private void HandleLoaded(object sender, RoutedEventArgs e)         {             const double offset = Math.PI;             const double step = Math.PI * 2 / 10.0;              SetPosition(C0, offset, 0.0, step);             SetPosition(C1, offset, 1.0, step);             SetPosition(C2, offset, 2.0, step);             SetPosition(C3, offset, 3.0, step);             SetPosition(C4, offset, 4.0, step);             SetPosition(C5, offset, 5.0, step);             SetPosition(C6, offset, 6.0, step);             SetPosition(C7, offset, 7.0, step);             SetPosition(C8, offset, 8.0, step);         }          private void SetPosition(Ellipse ellipse, double offset,             double posOffSet, double step)         {             ellipse.SetValue(Canvas.LeftProperty, 50.0                 + Math.Sin(offset + posOffSet * step) * 50.0);              ellipse.SetValue(Canvas.TopProperty, 50                 + Math.Cos(offset + posOffSet * step) * 50.0);         }          private void HandleUnloaded(object sender, RoutedEventArgs e)         {             Stop();         }          private void HandleVisibleChanged(object sender,             DependencyPropertyChangedEventArgs e)         {             bool isVisible = (bool)e.NewValue;              if (isVisible)                 Start();             else                 Stop();         }         #endregion     }