While the various animation classes that extend the Timeline class can be used to animate control properties directly in code, in order to declare and trigger animations using XAML alone, we need to use the Storyboard class. This is what is known as a container timeline, as it extends the abstract TimelineGroup class that enables it to contain child timelines.
Another container timeline class that the Storyboard class extends is the ParallelTimeline class and these classes enable us to group child timelines and to set properties on them as a group. When creating more complex animations, if all we need to do is to delay the start of a group of child timelines, we should use the ParallelTimeline class rather than the Storyboard class, as it is more efficient.
We could rewrite our earlier BeginTime example to use a ParallelTimeline element to delay the start of our last two timelines. Let's see what that might look like:
<Storyboard> <DoubleAnimation Storyboard...