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A completely new feature in Silverlight 3 is the ability to establish a local connection between loaded Silverlight applications.

Silverlight 3 enables property binding to CLR objects and other UI components via XAML – UI to UI binding. It is useful in a lot of scenarios and saves time for both developers and designers.

Example

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Syntax

{Binding Value, ElementName=MySlider}

where Value is property of a CLR object and MySlider is the name of this object

Hope that helps!

Syntax

Style cascading is accomplished by using the new BasedOn attribute of the Style class.

   1: <Style x:Name="Headline" TargetType="TextBlock">

   2:     <Setter Property="FontFamily" Value="Verdana" />

   3:     <Setter Property="FontSize" Value="14" />

   4: </Style>

   5: <Style x:Name="ImportantHeadline" TargetType="TextBlock" 

   6:     BasedOn="{StaticResource Headline}">

   7:     <Setter Property="Foreground" Value="Red" />

   8: </Style>        

   9: <Style x:Name="HomePageHeadline" TargetType="TextBlock" 

  10:     BasedOn="{StaticResource Headline}">

  11:     <Setter Property="FontSize" Value="18" />

  12: </Style>

Here we have a base style Headline that targets TextBlock elements and defines values for FontFamily and FontSize. Next we have another style ImportantHeadline which again targets TextBlock elements. Note here the additional attribute BasedOn(Line 6). By using it we are basing this style on the style defined by its value – Headline in this example. Here we set the Foreground property of the TextBlock to be Red.

When we use the ImportantHeadline style on a TextBlock we are going to have both of the values set in the Headline style(FontFamily, FontSize) and those set in ImportantHeadline(Foreground).

Then another style HomePageHeadline is defined. It is also based on the Headline style, but this time it overrides the base value set for FontSize. Now when we use the HomePageHeadline on a TextBlock we can see that it appears  with FontFamily Verdana and FontSize 18.

The results are as follows:

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Note: you can cascade styles on more than one level. Following the example above you can base another style on the HomePageHeadline and you will have 3 levels of cascading.

Hope that helps!

Merged Resource Dictionaries provide a way to define and split resources into separate files. By locating application resources in external file we can then reuse them between applications. This feature can be helpful in custom control development, but not only.

In Silverlight 2 resources cannot be factored into separate files and that leads to large App.xaml file holding application-wide shared resources. The same problem exists while developing custom controls. All default style keys must be specified in Themes/Generic.xaml which again leads to very large file.

One major point in building line-of-business applications is the data validation. You can’t go without it and that’s where Sillverlight 3 comes in handy. In that release Microsoft added advanced facilities for validating data via two-way databinding.

Following best practices and patterns you may have heard that it is good to separate your validation logic from the UI. That’s exactly the case with the built-in validation in Silverlight.

Let’s start with an example of a data form containing validation logic.

Silverlight 3 was just announced on MIX09 – I’m sure you are all pretty excited about the new features included in this release. There is a lot to talk about – offline support, styling, binding, controls, media, animation, graphics, etc.

This article aims to give you a brief overview of the new features as well as links to in-depth articles explaining the details.

Let’s start by organizing the new features in groups:

DataBinding

• Element to Element Binding – enables property binding to CLR objects and other UI components via XAML.

Introduction

When it comes to making calls to a Web Service in Silverlight you have no other way, but to do it async. In many scenarios this could be a problem and especially when you use data binding.

The Problem

Consider you have a business objects Merchant and Sale and the Merchant has property Sales of type List as shown on the class diagram.

The sales are loaded from a web service.