Ответ 1
Это то, что вы ищете?
<ListBox x:Name="lstBox" Grid.Row="0" Height="Auto" HorizontalAlignment="Stretch" Margin="5,5,5,5" VerticalAlignment="Top" ItemsSource="{Binding NewsItems,UpdateSourceTrigger=PropertyChanged}" >
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="LayoutTransform">
<Setter.Value>
<ScaleTransform x:Name="transform" />
</Setter.Value>
</Setter>
<Style.Triggers>
<EventTrigger RoutedEvent="Loaded">
<EventTrigger.Actions>
<BeginStoryboard>
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="Opacity" From="0" To="1" Duration="0:0:2" />
<DoubleAnimation Storyboard.TargetProperty="LayoutTransform.ScaleY" From="0" Duration="0:0:.2"/>
</Storyboard>
</BeginStoryboard>
</EventTrigger.Actions>
</EventTrigger>
</Style.Triggers>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>