A key frame animation's target values are defined by its KeyFrames property, which contains a collection of DoubleKeyFrame objects. Each DoubleKeyFrame defines a segment of the animation with its own target Value and KeyTime. When the animation runs, it progresses from one key value to the next at the specified key times.
There are three types of DoubleKeyFrame classes, one for each supported interpolation method: LinearDoubleKeyFrame, DiscreteDoubleKeyFrame, and SplineDoubleKeyFrame.
Unlike a DoubleAnimation, a DoubleAnimationUsingKeyFrames can have more than two target values. You can also control the interpolation method of individual DoubleKeyFrame segments.
When declaring a DoubleAnimationUsingKeyFrames in XAML, the order of the DoubleKeyFrame object elements is not significant, because the KeyTime controls the timing and therefore the order in which the key frames are executed. However, it is good markup style to keep the element order the same as the KeyTime sequence order.