XAML版本的：

 

<Window x:Class="StartAnimation.MainWindow"

         xmlns=""

         xmlns:x=""

         AllowsTransparency="True" WindowStyle="None"

         Title="MainWindow" Height="350" Width="525" RenderTransformOrigin=".5,.5">

   <Window.RenderTransform>

     <ScaleTransform x:Name="scale" />

   </Window.RenderTransform>

   <Window.Triggers>

     <EventTrigger  RoutedEvent="Window.Loaded">

       <BeginStoryboard>

         <Storyboard>

           <DoubleAnimation Storyboard.TargetProperty="ScaleX"

                           Storyboard.TargetName="scale" From="0" To="1"

                            Duration="00:00:01"

                            FillBehavior="HoldEnd"

                            AccelerationRatio=".5" />

           <DoubleAnimation Storyboard.TargetProperty="ScaleY"

                           Storyboard.TargetName="scale" From="0" To="1"

                            Duration="00:00:01"

                            FillBehavior="HoldEnd"

                            AccelerationRatio=".5" />

         </Storyboard>

       </BeginStoryboard>

     </EventTrigger>

   </Window.Triggers>

   <Border CornerRadius="6"    >

     <Border.Background>

       <RadialGradientBrush Center=".5,.5" ColorInterpolationMode="ScRgbLinearInterpolation" >

         <GradientStop Color="Green" Offset=".2"/>

         <GradientStop Color="LightGreen" Offset="1"/>

       </RadialGradientBrush>

     </Border.Background>

   </Border>

 </Window>

 

CS代码版本的：

 

    void MainWindow_Loaded(object sender, RoutedEventArgs e)

         {

             ScaleTransform transform = new ScaleTransform() { };

             this.RenderTransform = transform;

             this.RenderTransformOrigin = new Point(.5, .5);

             DoubleAnimation animtion = new DoubleAnimation()

             {

                 From = 0,

                 To = 1,

                 Duration = TimeSpan.FromSeconds(.5),

                 FillBehavior = FillBehavior.HoldEnd,

                 AccelerationRatio = .5

 

            };

             transform.BeginAnimation(ScaleTransform.ScaleXProperty, animtion);

             transform.BeginAnimation(ScaleTransform.ScaleYProperty, animtion);

         }