Introduction to .NET 3.0, C# 3.0 and LINQ
Andrew Troelsen
MCP, MCT, C# MVP
An Intertech Course
Copyright © Intertech, Inc. 2006. All Rights Reserved.

Introduction to .NET 3.0, C# 3.0 and LINQ
Objectives
• Understand the scope of .NET 3.0
• Introduce Windows Presentation Foundation (WPF)
• Introduce Windows Communication Foundation
(WCF)
• Introduce Windows Workflow Foundation (WF)
• Examine proposed C# 3.0 Language Changes
• Preview LINQ / LINQ to Sql / LINQ to XML
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Introduction to .NET 3.0, C# 3.0 and LINQ
The Scope of .NET 3.0
• .NET 3.0 is an augmentative release of the .NET base class
libraries:
• Everything you currently know about .NET 1.0 / 1.1 / 2.0 still
applies 100%.
• For example, Windows Forms / .NET Remoting are not depreciated.
• .NET 3.0 is not only for Vista development:
• Windows XP and Windows Server 2003 can be used to develop and
execute .NET 3.0 software with no problems.
• However, .NET 3.0 software can perform ‘better’ on Vista given the
new driver model (etc.).
• .NET 3.0 is natively part of Vista.
• XP / Windows Server requires installation of the .NET 3.0 SDK /
.NET 3.0 runtime.
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Introduction to .NET 3.0, C# 3.0 and LINQ
The Scope of .NET 3.0
• While .NET 3.0 is officially released, the development tools
are in beta!
• Microsoft has beta plug ins which allow you to build .NET 3.0
applications (Wizards, designers, project templates, etc).
• However, their current functionality (in some cases) is quite limited.
• www.msdn.microsoft.com/windowsvista/downloads
The .NET 3.0 SDK can
Also be found here, for
WinXP and Windows Server
Machines.
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Introduction to .NET 3.0, C# 3.0 and LINQ
The Scope of .NET 3.0
• Currently, C# 3.0 / LINQ are in beta.
• Thus, when you build .NET 3.0 software, you are doing so
with the C# 2.0 compiler!
• C# 3.0 (and VB 9.0) / LINQ are not set to be released until
Spring 2007.
• However, you can download the CTPs for LINQ get ahead of
the curve.
• The LINQ CTP includes:
• C# 3.0, VB 9.0 compilers.
• LINQ assemblies.
• Numerous white papers / code samples.
• www.msdn.microsoft.com/data/ref/linq
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Introduction to .NET 3.0, C# 3.0 and LINQ
The Scope of .NET 3.0
• .NET 3.0 is represented by three core
technologies:
• Windows Presentation Foundation (WPF)
• Windows Communication Foundation
(WCF)
• Windows Workflow Foundation (WF)
• First up, WPF…
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Introduction to .NET 3.0, C# 3.0 and LINQ
WPF
• The Windows Forms API is a well know model for building
desktop apps with the .NET platform.
• However, building a ‘real world’ WinForms application demands
mastering several diverse and asymmetrical APIs.
Application Requirement .NET 2.0 Solution
Core Form / Control model Windows Forms
2D Graphics GDI+ (System.Drawing.dll)
3D Graphics DirectX APIs
Live Video Feeds Windows Media Player APIs
Fixed Style Documents Programmatic manipulation of PDF files.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WPF
• One of the major goals with WPF is to provide a
single, symmetrical model for desktop development.
• With WPF, all necessary technologies are baked into the
same assemblies (much easer!).
Application Requirement .NET 3.0 Solution
Core Form / Control model Windows Presentation Foundation
2D Graphics Windows Presentation Foundation
3D Graphics Windows Presentation Foundation
Live Video Feeds Windows Presentation Foundation
Fixed Style Documents (PDFs) Windows Presentation Foundation
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Introduction to .NET 3.0, C# 3.0 and LINQ
WPF
• Another major difference between WinForms and WPF is
support for a separation of concerns via XAML.
• XAML is essentially, desktop markup.
• WPF apps allow you to separate the look and feel of your apps from
the logic which drives it.
• Use of XAML however, is entirely optional.
• If you wish, you can take the 100% pure code approach.
• You could take a 100% pure XAML approach.
• Or (most commonly) take a code file approach (XAML / Code split).
• When taking the code file approach, you will find the process
of building a WPF app is eerily similar to building an ASP.NET
web app.
• Partial classes, markup + code, XAML to code mappings, etc.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WPF
• The major motivation for XAML is the separation of
concerns.
• Programmers can use dev tools (VS 2005) to do the fun stuff
(write .NET code).
• Graphical minded individuals can using design tools
(Expression Interactive Designer) to build a rich UI interface.
• The XAML files can then be passed to us and integrated into
our projects.
• Finally! A way for programmers and designers to live in
peace!
• More information on MS Expression products:
• www.microsoft.com/products/expression
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Introduction to .NET 3.0, C# 3.0 and LINQ
WPF
• In addition to the benefits already mentioned, WPF
offers a number of additional bells and whistles:
• The ability to host a WPF application within a web browser
(via XAML browser applications…XBAP).
• Numerous layout managers to position controls.
• A new (very slick) data binding engine.
• Support for styles and templates, to ‘skin’ your WPF apps.
• WPF relies entirely on vector graphics, allowing an image to
be automatically resized to fit the size and resolution of the
screen it's displayed on.
• Integrated animation / 3D-rendering services.
• Support for interop-ing with legacy UI models (Windows
Forms, ActiveX, etc).
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Introduction to .NET 3.0, C# 3.0 and LINQ
WPF
• Demo! A 100% Pure Code WPF Application.
• Authored via notepad++ / csc.exe.
• Composed on a single window, button widget.
• Compiled via *.rsp files
• Demo! A 100% XAML Application.
• Same app, two *.xaml files.
• Event handling wrapped in <CDATA>.
• Compiled via msbuild / *csproj.
• Demo! Code-file Application.
• Xaml + Code files.
• Use of partial classes
• Created w/ VS 2005 “Orcas“
• BAML investigated!
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Introduction to .NET 3.0, C# 3.0 and LINQ
WCF
• Windows Communication Foundation (WCF)
integrates numerous distributed technologies.
• Similar to WPF, WCF lives to provide symmetry.
• Today building a distributed app is complex at best.
• Too many diverse APIs (COM+, MSMQ, web services,
remoting).
• Each has a different object model, configuration tools,
documentation, etc.
• The current approach is complex, confusing and hard to
maintain.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WCF
• WCF provides a single, extendable object model.
• Using *.config files, you can radically change the underlying
plumbing via markup (channels, transports, etc).
• SvcConfigEditor.exe can build client-side and server-side *.config
files.
This WCF *.config file
is part of the .NET 3.0
SDK.
Future versions of VS 2005
Will no-doubt provide similar
Functionality.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WCF
• Support for strongly typed as well as untyped messages.
• This approach allows .NET applications to share custom types simply
and efficiently.
• Software created using other platforms (such as Java) can consume
streams of loosely typed XML.
• Support for several endpoints to allow you to choose the most
appropriate plumbing to transport data to and fro.
• HTTP, HTTP + SOAP
• MSMQ
• Named Pipes
• TCP
• COM+
• Any custom endpoint you might dream up…
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Introduction to .NET 3.0, C# 3.0 and LINQ
WCF
• WCF applications are designed by specifying the A, B, Cs:
• Address: Where does this service life?
• Bindings: Which protocols are used to access it?
• Contracts: Once I get there, what will I find?
• The Service Configuration Tool can be used to specify the set
of bindings and address of a given service.
• The contract of a WCF service are defined in code.
• In many ways, these A, B, Cs are a re-telling of WSDL
descriptors.
• In other ways, these A, B, Cs are a re-telling to the sort of data
found within a .NET remoting configuration file.
• The short answer is, if you have worked with XML web
services or .NET remoting…
• …you’ll feel right at home with WCF.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WCF
• Building a WCF service is very simple:
• Numerous attributes can be used to control service behaviors.
• Functionality is (typically) exposed using strongly typed interfaces.
• The collection of WCF types is typically bundled into a .NET *.dll.
[ServiceContract]
public interface ICarOrder
{
// Allows caller to place and order and obtain
// an order ID.
[OperationContract]
int PlaceOrder(string make, string color, double price);
// Allows caller to get current status of the order.
[OperationContract]
string CheckOrderStatus(int orderID);
}
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Introduction to .NET 3.0, C# 3.0 and LINQ
WCF
• WCF Services can be hosted from a variety of locations.
• Any *.exe assembly.
• Within IIS
• From WAS (Vista-specific activation service).
• The ServiceHost type is used (directly or indirectly) to host the
service itself.
• Anything can be a consumer of WCF services:
• *.exe, *.dll, web page, WCF service, etc.
• .NET, COM, Java, C++, etc.
• Linux, Mac, XP, Vista, etc.
• Simply adjust the bindings to ensure the correct ‘reach’.
• Client side proxies can be generated with svcutil.exe or VS 2005.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WCF
• WCF Demo!
• A WCF service assembly, build with interface based
programming techniques.
• A console based WCF host (with related *.config file).
• A console based WCF client (with related *.config file).
• Remember! Both *.config files can be visual
created using the Service Configuration Tool.
• Furthermore, the proxy can be automatically generated using
svcutil.exe / VS 2005.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WF
• Windows Workflow Foundation (WF) is perhaps the 'strangest'
element of .NET 3.0.
• Earlier versions of .NET have no direct equivalent.
• However, the idea of ‘workflow enabled applications’ is not new.
• Using WF, you are able to model directly in your assembly
the workflows used by your applications.
• Workflows = business processes.
• The WF runtime engine can then execute these tasks as your
application is running.
• The same model used to author code can be shared with other non-
technical staff.
• Thus, no need to maintain separate docs to illustrate to others what
your code is doing.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WF
• WF enabled applications consist of any number of
‘activities’.
• These activities are connected via decision / iteration paths.
• Paths can run in parallel.
• WFs can be sequential or state machine.
• Each activity maps to real types in real
namespaces.
• Thus, you can interact with your activities directly, or simply
allow the WF runtime to process them as required.
• Visual Studio 2005 “Orcas” supports numerous
designers with allow you to model your business
process.
• *.Designer.* files are updated automatically.
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Introduction to .NET 3.0, C# 3.0 and LINQ
WF
• WF Demo!
• Illustrate the WF designer tools.
• Examine baked in activities.
• Simple WF example.
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Introduction to .NET 3.0, C# 3.0 and LINQ
C# 3.0 Language Features
• Recall that C# 3.0 / VB 9.0 supports numerous
features which make it possible to interact with the
LINQ technology set.
• Also recall that these updates (and LINQ) are currently in
beta, and are not to be released formally until Spring 2007
(or so).
• Here, we will survey some (but not all) of the proposed
changes.
• Due to time constraints, an overview of the lambda operator (=>)
will not be covered.
• In a nutshell, lambda expressions are a grand simplification for
working with delegate types.
• Lambdas not currently supported in VB 9.0!
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Introduction to .NET 3.0, C# 3.0 and LINQ
C# 3.0 Language Features
• Many features can be used directly ‘as-is’ with little
concern for LINQ or lambda expressions (a
hallmark of functional languages).
• However, as mentioned, when using LINQ, many of these
new language constructs make much more sense.
• Before we examine LINQ, here is a quick overview of the
core C# language features.
• VB 9.0 has very similar syntax for most of these
features.
• VB-minded developers can consult the LINQ documentation
for specifics.
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Introduction to .NET 3.0, C# 3.0 and LINQ
C# 3.0 Language Features
• Implicitly typed local variables using ‘var’.
• Compiler infers the underlying data type, based on assignment.
• NOT a Variant! NOT script code! Strongly typed!
• Greatly simplifies working with LINQ query expressions.
static void Main()
{
// Implicitly typed local variables.
var myInt = 0;
var myBool = true;
var myString = \"Time, marches on...\";
// Print out the underlying type.
Console.WriteLine(\"myInt is a: {0}\", myInt.GetType().Name);
Console.WriteLine(\"myBool is a: {0}\", myBool.GetType().Name);
Console.WriteLine(\"myString is a: {0}\", myString.GetType().Name);
}
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Introduction to .NET 3.0, C# 3.0 and LINQ
C# 3.0 Language Features
• Extension methods allow you to add new functionality to a
pre-compiled type.
• Allows for easy augmentation of types for which you do not have
source code.
• Again, very helpful for LINQ.
• First parameter of a method can now be marked with \"this
<dataType>\" to control which type is being extended.
• Other namespaces can import the definition of the defining
namespace.
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Introduction to .NET 3.0, C# 3.0 and LINQ
static class MyExtensions
{
// This method allows any object to display the assembly This extension method applies
// it is defined in.
public static void DisplayDefiningAssembly(this object obj)
To everything (System.Object).
{
Console.WriteLine(\"{0} lives here:\\n\\t->{1}\\n\", obj.GetType().Name,
Assembly.GetAssembly(obj.GetType()));
}
// This method allows any integer to reverse its digits.
// for example, 56 would return 65. This extension method only
public static int ReverseDigits(this int i)
{
Applies to integers.
// Translate int into a string, and then
// get all the characters.
char[] digits = i.ToString().ToCharArray();
// Now reverse items in the array.
Array.Reverse(digits);
// Put back into string.
string newDigits = new string(digits);
// Finally, return the modified string back as an int.
return int.Parse(newDigits);
}
}
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Introduction to .NET 3.0, C# 3.0 and LINQ
static void Main(string[] args)
{
// Old types, new identity!
int myInt = 12345678;
myInt.DisplayDefiningAssembly();
System.Data.DataSet d = new System.Data.DataSet();
d.DisplayDefiningAssembly();
System.Media.SoundPlayer sp = new System.Media.SoundPlayer();
sp.DisplayDefiningAssembly();
// Use new integer functionality.
Console.WriteLine(\"Value of myInt: {0}\", myInt);
Console.WriteLine(\"Reversed digits of myInt: {0}\",
myInt.ReverseDigits());
}
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Introduction to .NET 3.0, C# 3.0 and LINQ
C# 3.0 Language Features
• Object initialization syntax allows you to set
property values (or public field values) at the time
of creation.
• Can also call custom constructors.
• Massive time saver.
• Assume a Rectangle class which defines two
properties (TopLeft, BottomRight) that each get / set
a Point type.
• The Point type has two properties (X, Y).
• Thus, Rectangle ‘has’ two Points.
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Introduction to .NET 3.0, C# 3.0 and LINQ
C# 3.0 Language Features
• The ‘old school’ approach requires us to author numerous
lines of code.
• The ‘new school’ approach is much more compact…
// Old school approach.
Rectangle r = new Rectangle();
Point p1 = new Point(); // New school approach.
p1.X = 10; Rectangle myRect = new Rectangle
p1.Y = 10; {
r.TopLeft = p1; TopLeft = new Point { X = 10, Y = 10 },
Point p2 = new Point(); BottomRight = new Point { X = 200, Y = 200}
p2.X = 200; };
p2.Y = 200;
r.BottomRight = p2;
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Introduction to .NET 3.0, C# 3.0 and LINQ
C# 3.0 Language Features
• Anonymous types allow you to model the
‘shape’ of data without concern for it’s
functionality.
• Very helpful for LINQ queries.
• Compiler generates a full blown class type in the
background.
• Anonymous types always:
• Are constructed with the default constructor.
• Extend System.Object (with value-based overrides).
• Map name/value pairs into properties with backing
fields.
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Introduction to .NET 3.0, C# 3.0 and LINQ
// Make an anonymous object representing a car.
var myCar = new {Color = \"Bright Pink\", Make = \"Saab\", CurrentSpeed = 55};
[CompilerGenerated]
public sealed class <Projection>f__0
{
// You are given a default constructor.
public <Projection>f__0();
// As well as a canned implementation of each virtual
// member from System.Object
public override bool Equals(object);
public override int GetHashCode();
public override string ToString();
// As well, properties are used to wrap...
public string Color { get; set; }
public int CurrentSpeed { get; set; }
public string Make { get; set; }
// ... each private member variable.
private string _Color;
private int _CurrentSpeed;
private string _Make;
}
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Introduction to .NET 3.0, C# 3.0 and LINQ
LINQ
• LINQ (Language Integrated Query) allows .NET languages to
create strongly typed query expressions.
• Full support for object representation.
• Compiler checked, IntelliSense support, debugging support, etc.
• LINQ queries are created using any number of ‘query
operators’ or related method calls in the object model.
• Modeled after SQL queries.
• The twist is that a LINQ query expression can be executed
against:
• Relational databases.
• XML documents
• Any object implementing IEnumerable<T>.
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Introduction to .NET 3.0, C# 3.0 and LINQ
LINQ
• LINQ offers a unified solution to the problem of
obtaining and manipulating ‘data’.
• Under .NET 2.0, we were forced to learn unique APIs to gain
access to various forms of data.
• ADO.NET, XML namespaces, collection methods, etc.
• Using LINQ, we can apply the same operators /
statements to a wide variety of data stores.
• Relational data, containers and XML docs.
• Third parts can extend LINQ (via extension methods) to query
over other data stores.
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Introduction to .NET 3.0, C# 3.0 and LINQ
LINQ
• Demo! LINQ over containers.
• Examining query operators.
• Building query expressions.
• Check out the LINQ object model.
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Introduction to .NET 3.0, C# 3.0 and LINQ
Wrap up!
• This Oxygen Blast presentation only scratched the surface of
WPF / WCF/ WF / LINQ / C# 3.0.
• Want more?
A 1-Day .NET 3.0 Intertech Boot Camp
- Sponsored by Microsoft and Apress.
- Content delivered by Apress authors.
- Hands on lab time (your computer or ours).
- March 29th, 2007.
- www.DevBlitz.com
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Introduction to .NET 3.0, C# 3.0 and LINQ
Wrap up!
• .NET 3.0 is an augmentative release to the .NET
BCL.
• WPF: Integrated desktop / Smart Client API.
• WCF: Integrated communications API.
• WF: Allows for integration of ‘workflow enabled
applications’.
• C# / VB 9.0 / LINQ are due out Spring 2007.
• C# / VB 9.0 each support numerous language
enhancements, most of which are their to support LINQ
technologies.
• LINQ provides a symmetrical manner in which to interact
with ‘data’ in the broad sense of the term.
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