In a given xaml, there is a part:
<ColorAnimation Storyboard.TargetProperty="Background.(SolidColorBrush.Color)" To="Black" Duration="0:0:3"/> If I specify only "Background", then it doesn't work. Why? Where can I get some info about making path?
P.S.: I seen some really crazy path, like "(blablabla).(blablabla).(blablabla.blablabla)" and it makes me nervous, because I can't find what does it means easily...
It doesn't work if you only specify Background because the storyboard animates a color, and this color is the Color property of the Background property.
Background is a brush, so it could contain any type of brush. In order to access the Color the brush needs to be converted to a SolidColorBrush.
This is basically what the expression Background.(SolidColorBrush.Color) does. It converts Background to a SolidColorBrush and then accesses the Color property from it.
In c# code you would write
((SolidColorBrush)Background).Color = someColor; 
Brush. Thanks. The only question left is syntax. I would expect something like "((SolidColorBrush)Background).Color", but in xaml it appears as Background.(SolidColorBrush.Color). Do you know any reference to this? Type conversion xaml gives TypeConverters as result in google.type-qualified property.Try this
Example1
<Button> <Button.Triggers> <EventTrigger RoutedEvent="Loaded"> <BeginStoryboard> <Storyboard> <ColorAnimation Storyboard.TargetProperty="Background.Color" From="Transparent" To="Red" Duration="0:0:0.1"></ColorAnimation> </Storyboard> </BeginStoryboard> </EventTrigger> </Button.Triggers> </Button> example2
<Grid> <Button x:Name="Button"></Button> <Grid.Triggers> <EventTrigger RoutedEvent="Loaded"> <BeginStoryboard> <Storyboard> <ColorAnimation Storyboard.TargetName="Button" Storyboard.TargetProperty="Background.Color" From="Transparent" To="Green" Duration="0:0:0.1"></ColorAnimation> </Storyboard> </BeginStoryboard> </EventTrigger> </Grid.Triggers> </Grid> 
Backgroundis of aBrushtype and this isColorAnimationwhich can animateColorthat is published bySolidColorBrush. For rules checkPropertyPath XAML Syntax"Background.Color"is working in my case. But thisSolidColorBrushpart inside brackets looks like type conversion and given description (in link) is very poor, limited and I feel it is incomplete. Do you know any better one?Background.Colorin case ofSolidColorBrushwill work just as well. Both cases will fail if there is noColorproperty justBackground.(SolidColorBrush.Color)expects it to beSolidColorBrushwhereBackground.Colorwill be happy with anyColorproperty so if you would have anotherBrushtype withColorproperty it will work as well