Вы можете использовать EventTriggers для захвата событий MouseEnter и MouseLeave в XAML.
Вот простой пример изменения фона StackPanel в сетке:
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<StackPanel Grid.Row="1" Background="Blue">
<StackPanel.Style>
<Style>
<Style.Triggers>
<EventTrigger RoutedEvent="StackPanel.MouseEnter">
<EventTrigger.Actions>
<BeginStoryboard>
<Storyboard>
<ColorAnimation
AutoReverse="False"
Duration="0:0:1"
From="Blue" To="Red"
AccelerationRatio="1"
Storyboard.TargetProperty="(StackPanel.Background).(SolidColorBrush.Color)"
FillBehavior="HoldEnd">
</ColorAnimation>
</Storyboard>
</BeginStoryboard>
</EventTrigger.Actions>
</EventTrigger>
<EventTrigger RoutedEvent="StackPanel.MouseLeave">
<EventTrigger.Actions>
<BeginStoryboard>
<Storyboard>
<ColorAnimation
AutoReverse="False"
Duration="0:0:1"
From="Red" To="Blue"
AccelerationRatio="1"
Storyboard.TargetProperty="(StackPanel.Background).(SolidColorBrush.Color)"
FillBehavior="HoldEnd">
</ColorAnimation>
</Storyboard>
</BeginStoryboard>
</EventTrigger.Actions>
</EventTrigger>
</Style.Triggers>
</Style>
</StackPanel.Style>
</StackPanel>
</Grid>