属性动画 是通过 Storyboard 来改变属性值

WPF 精修篇 属性动画_WPF

<Rectangle x:Name="rect" Width="200" Height="200" >
<Rectangle.Fill>
<SolidColorBrush Color="Beige" x:Name="color"></SolidColorBrush>
</Rectangle.Fill>
<Rectangle.Triggers>
<EventTrigger RoutedEvent="MouseEnter">
<EventTrigger.Actions>
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Duration="0:0:1" Storyboard.TargetName="rect" Storyboard.TargetProperty="Width" To="400"></DoubleAnimation>
<ColorAnimation Duration="0:0:1" Storyboard.TargetName="color" Storyboard.TargetProperty="Color" To="Cyan"></ColorAnimation>
<DoubleAnimation Duration="0:0:1" Storyboard.TargetName="rect" Storyboard.TargetProperty="Height" To="400"></DoubleAnimation>
</Storyboard>

</BeginStoryboard>
</EventTrigger.Actions>

</EventTrigger>
<EventTrigger RoutedEvent="MouseLeave">
<EventTrigger.Actions>
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Duration="0:0:1" Storyboard.TargetName="rect" Storyboard.TargetProperty="Width" To="200"></DoubleAnimation>
<ColorAnimation Duration="0:0:1" Storyboard.TargetName="color" Storyboard.TargetProperty="Color" To="Beige"></ColorAnimation>
<DoubleAnimation Duration="0:0:1" Storyboard.TargetName="rect" Storyboard.TargetProperty="Height" To="200"></DoubleAnimation>

</Storyboard>
</BeginStoryboard>
</EventTrigger.Actions>
</EventTrigger>
</Rectangle.Triggers>


</Rectangle>