Common mistakes

Common mistakes

Table 14.2 lists the mistakes that occur most often when creating animations and multimedia applications.

Table 14.2. Common mistakes in animation and multimedia work

Problem	Cause	Fix
the animation does not compile or has no effect	an ordinary C# property or field is animated	animate a dependency property; register one for your own class
a rotation or scale animation has no effect	RenderTransform is not set (it holds an immutable identity transform) or the path contains an error	set <RotateTransform/> in advance, check (UIElement.RenderTransform).(…)
after an animation, assigning the property in code is ignored	FillBehavior="HoldEnd" holds the value	BeginAnimation(property, null) or FillBehavior="Stop" and Completed
Cannot animate … because the object is sealed or frozen	the brush or transform is frozen (from a style, Brushes.Gray)	assign a new copy new SolidColorBrush(…) or Clone()
Pause/Stop have no effect on a storyboard	it was started without isControllable: true or for a different element	Begin(this, true) and the same element in all calls
the player buttons do not work	LoadedBehavior has the default value Play	LoadedBehavior="Manual"
the media file is not found after the build, MediaFailed	the file is not copied or the path is relative	Content, Copy if newer, a path based on AppContext.BaseDirectory
the interface "lags"	dozens of Width/Margin animations, LayoutTransform	animate RenderTransform, Opacity, BitmapCache, Freeze