There are several key differences between Silverlight and Flex: - Silverlight uses XAML and .NET languages while Flex uses MXML and ActionScript. Silverlight code is compiled into .NET assemblies while Flex code is compiled into SWF files. - Silverlight provides better performance through native execution on the CLR, while Flex has slower execution through the Flash virtual machine. - Expression Blend is a more powerful editor than Flex Builder. - Silverlight supports additional languages like C# and generics, while Flex only supports ActionScript. - Silverlight provides better threading and asynchronous task support compared to Flex. - Binding and layout are more complex in Silverlight compared to the easier

1. 1.Difference between Custom Control and User Control in Silverlight
S.No Custom Control User Control
1 A loosely coupled control w.r.t A tightly coupled control w.r.t code
code and UI and UI
2 Derives from Control Derives from UserControl
3 Defines UI in the Defines UI as a normal XAML
ResourceDictionary
4 UI can be skinable Child controls can skinable only
5 Has Dynamic layout Has static layout
6 UI can be changed in different UI is fixed and can't have different
project look in every project
7 Has full toolbox support Can't be added to the toolbox
8 Defines a single control Defines a set of controls
9 More flexible Not much flexible like Custom Control
10 Requires in depth knowledge of Does not require depth knowledge of
Silverlight UI Model UI Model
2.Difference between DataContext and ItemsSource property in Silverlight
S.No DataContext property ItemSource property
1 DataContext expects an object ItemsSource expects IEnumerable type
type objects
2 DataContext is a dependency ItemsSource is defined by the
property is exposed by ItemsControl class. All the descendants
FrameworkElement base class of FrameworkElement can utilize the
DataContext property and set an object
to its value.
Note: But we can only set a type of
IEnumerable(or instance of class that
derives from).
3 DataContext does not generate In terms of ItemsSource property, it is
template, it only used to hold mainly used to generate template
common data for other controls to regardless of you set it in XAML or in
bind. the code behind.
4 DataContext is mainly used to But for ItemsSource, it is not used to
hold common data that other child share data in the visual tree. It is only

2. want to share. Thus it can be valid for the element that defined.
inherited by other child elements There is still one thing to be noted is
without problem. that the child element can override the
DataContext of the perent DataContext
no mater directly or indirectly.
Example(s):
Suppose we have a Person Class which has a property Name. Now in Xaml we can say like:
<StackPanel x:Name="Parent">
<StackPanel.Resources>
<local:Person x:Key="person">
</StackPanel.Resources>
<ListBox ItemsSource="{Binding Source={StaticResource person}}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBox Text="{Binding Path=Name}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
If you run this code in the ListBox you will get to see values depending on List<Person> object. But
if we change the ItemsSource to DataContext then you will be not able to see anything because
DataContext doesn't generate templates in any cases. If you set datacontext still you have to set the
ItemsSource property like this:
<ListBox DataContext="{Binding Source={StaticResource person}}" ItemsSource="{Binding}">
Summary:
In a word, if we have several child elements that will share a common data source, we can set
DataContext property for the parent elements. And we use ItemsSource for ItemsSource in most
cased to generate template. Like:
<StackPanel DataContext="{Binding Person"}>
<TextBox Text="{Binding FName}"/>
<TextBox Text="{Binding LName}"/>
</StackPanel>
3.Difference between Silverlight and Flex
S.No Silverlight Flex
1 Execution Mechanism: Execution Mechanism:
Power of Native execution of Slow execution for iterative executions
CLR instead of Flash's Action
Script Interpretator

3. 2 Editing facility: Editing facility:
Expression Blend is really cool Flex Builder is not that much good
and more advanced editor then editor when compare with Expression
Flex Builder Blend
3 Multilanguages Support: Multilanguages Support:
Power of other languages, No generics, No other languages, No
provides Generics and Linq etc linq.
4 Threading and Asynchronous Threading and Asynchronous Tasks:
Tasks:
Unavailable
Available
5 Form layouting and binding: Form layouting and binding:
Binding in Silverlight is way more Better in Adobe Flex.The most easy
cumbersome.Binding requires way to create new components, you
component naming and does not can have mxml derive from any
support instance expressions like control and extend them with extensive
flex does, though two way binding.
binding is good in silverlight but
you have to write long codes for
multiple bindings for one math
expression.
6 Where primarily used: Where primarily used:
Silverlight is used for extremely We use flex for data applications, those
rich graphics and animation are simple form processing
applications
7 Search Engine Friendly: Search Engine Friendly:
XAML is Search Engine Friendly MXML markup language is not Search
Engine Friendly
8 Client / Server Technology: Client / Server Technology:
Silverlight can be developed for a Flex is a client based application tool
server or client environment.
9 Release Date: Release Date:
Before it was called Silverlight, it Adobe Flex was originally released in
was known as Windows 2004 by Macromedia. The third
Presentation version (Flex Builder 3) became
Foundation/Everywhere (WPF/E) available in 2008.
and was first released in 2007.
Silverlight 2 became available in
October 2008. Silverlight 3 was

4. released in July 2009.
10 Language Differences: Language Differences:
Alternatively, Microsoft Adobe Flex uses MXML markup
Silverlight uses the XAML language and actionscript to build
language as a placeholder for layout/graphic user interfaces. To
media files, shapes and images. It create components, it works with
works with all .NET languages ActionScript (the object oriented Flash
and JavaScript for interactive and language). After the code is completed,
component features. Completed it needs to be compiled by the Flex
code is compiled with the .NET Application Server.
assemblies and compressed into a
ZIP file.
11 Data Transfer: Data Transfer:
No such format for data transfer. Data transfer via the proprietary AMF
Will have to stick to SOAP and using WebORB, Fluorine, etc is faster
REST web services(for now). than traditional web services.
12 Debugging: Debugging:
Debugging using Visual Studio is Debugging is a bit of a hassle.
very easy.
13 Webservice Access: Webservice Access:
Accessing web services is very Accessing web services requires
easy. Just add a reference to the manual creation of ActionScript proxy
WebService in Visual Studio and classes. We can automate this by using
lookup reference.cs for the good FlexTense though.
stuff
14 Componenet Size: Component Size:
Size of the Silverlight component Size of the compiled SWF file is
is larger. smaller than that of the uncompressed
Silverlight component.
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