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Styles in Silverlight: Everything a Developer Needs To Know

This post is a summary on my 4 part series covering everything I think a developer needs to know about Styles in Silverlight in order to work with them in XAML or programatically. The overview of the series is as follows. All of the topics link to the original, more detailed article: feel free to explore the parts that interest you most!

Introduction

Inheritance, Precedence and Other Advanced Topics

  • Re-Using Styles for Different Types: the TargetType of the Style can be a parent type of the target object as long as it only sets properties of the parent type.
  • Style Inheritance: The BasedOn property - inheriting styles can be done using the BasedOn property. Styles support single inheritance and the depth of inheritance is not limited.
  • Implicit Styling - in Silverlight 4 the default styles of elements on a page / control can be specified in a simple way using implicit styles.
  • Style Precedence: a Style's Setters only get applied if the object's particular property is not animated, not set locally and not set in the control template belonging to the object.
  • Style Setter Precedence: setters specifying the value of the same property may be declared within the same Style. The last one of them has the highest precedence and will be used.

Further Advanced Topics

  • Style is a Dependency Property. This means that it supports the following features:
    • Data binding: it's possible to bind styles on to another - even though this is probably a very rare real world scenario.
    • Property changed notifications: it's not possible to directly subscribe to property changed notifications for the Style property due to the feature missing in Silverlight, however there is a complicated, but working workaround available to detect when the Style is being changed.
    • ClearValue: unsetting the value of a Style is not the same as setting it to null. When wanting to reset or clear the style, ClearValue is the method to be used.
  • Declaring Styles In Code Behind is possible, it results in more complex code though then doing the same thing in XAML.
  • Other Notes About Styles
    • Only Dependency Properties Can Be Styled: styling CLR properties will result in either a compile time or runtime error.
    • Not All Classes Have Styles: only Ones Derived From FrameworkElement have the Style property and thus can be styled. All of the built-in visual controls, the Control and UserControl class are descendants of this class. It's worth remembering this when creating custom classes that might need to be styled.

Manipulating Styles at Runtime

I hope this summary on styles in Silverlight was helpful.

Interested in an easy to style, very performant Silverlight / WPF charting library? Give the free version of Visiblox a try!

Comments

Great post and (great post series) Gergely. Certainly came in useful for me! :)

 
Posted by Sam Hogarth

Thanx for this great links. It would be very useful to create one PDF for print? Like some small ebook about styles in SL. Then someone else publish series of blog post about dependency property/object tips/trick or similar topic, and by end of the year we would have great ebook, with all the information someone could look for :)

 
Posted by Hrvoje

Great summary!

 
Posted by Johnny

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