public Nullable<TimeSpan> Duration { get; set; }

Public Property Duration As Nullable(Of TimeSpan)
	Get
	Set

public:
property Nullable<TimeSpan> Duration {
	Nullable<TimeSpan> get ();
	void set (Nullable<TimeSpan> value);
}

member Duration : Nullable<TimeSpan> with get, set

Property Value

The property Duration can be set to override the duration of the animation. If Duration is greater than the length of the animations in the blend group, the blend group will be repeated using the defined loop behavior (see LoopBehavior).

The effective duration depends on the Speed: For example, an animation with a delay of 3 seconds, a duration of 10 seconds and a speed ratio of 2 will start after 3 seconds and run for 5 seconds with double speed.

The default value is , which indicates that the duration is 'automatic' or 'unknown'. In this case the blend group plays exactly once. A duration of MaxValue can be set to repeat the animation forever.

Reference