Represents a collection of DoubleKeyFrame objects that can be individually accessed by index.
One or more DoubleKeyFrame object elements that define the key frames for the animation. These can be any combination of <LinearDoubleKeyFrame .../>, <DiscreteDoubleKeyFrame .../>, and <SplineDoubleKeyFrame .../>. Object elements defined here become members of the KeyFrames collection when scripting accesses the KeyFrames property at run time.
DoubleKeyFrameCollection defines no methods or properties beyond the basic Collection methods and properties. Methods such as Add or GetItem will expect or return objects that are of type DoubleKeyFrame. DoubleKeyFrame itself is an abstract object, so the returned objects might be DiscreteDoubleKeyFrame, LinearDoubleKeyFrame, or SplineDoubleKeyFrame.
The XAML syntax for properties that use a DoubleKeyFrameCollection is an example of implicit collection syntax, in which you can omit an actual DoubleKeyFrameCollection object element. Explicitly including a DoubleKeyFrameCollection object element is permissible XAML syntax and might be useful if you intend to name the collection in XAML and manipulate its contents through script later.
In the DoubleKeyFrameCollection, the order of the DoubleKeyFrame object elements is not significant for purposes of how the animation runs, because the KeyTime property controls the timing and, therefore, the order in which the key frames are executed. If a DoubleKeyFrameCollection is established with XAML, the items in the collection are in the same order as the child elements are declared. It is good markup style as well as good coding style to keep the item/element order the same as the KeyTime sequence order.