XAML版本的：
<Window x:Class="StartAnimation.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
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);
}