Module 2: C# 3.0 Language Enhancements (PowerPoint Slides) Jordan .NET User Group (Jordev) Community Material Mohamed Saleh

1. Visual Studio 2008 Training
3.5 RTM
Mohamed Saleh
MohamedSaleh@live.com
www.jordev.net
www.geeksconnected.com/mohamed

2. Module 2:
C# 3.0 Language
Enhancements

3. Overview
Automate the process of creating properties
Enhance the objects and collections using the
Initializers
Create implicitly typed local variables
Extend existing types using Extension Methods
Write the new lambda expressions
Using the new features in multi-framework versions

4. Automatically Implemented Properties
Auto-Implemented Properties Overview
Auto-Implemented Properties can handle the trivial
implementation of getter and setter.
The compiler will generate hidden backing fields with the
implementation.
This feature is related to the compiler and not the
Framework Version or the Intermediate Language.
The Auto-Implemented Properties can be implemented
using the following syntax:
public string Name { get; set; }

5. Lab 1: Using Auto-Implemented Properties
Using the Automatic Implemented
Properties.
Creating read-only and write-only
properties.
Using Automatic Implemented Properties
with multi-framework versions.
Examining the effects of the Automatic
Implemented Properties on the generated
intermediate language.

6. Object and Collection Initializers
Object Initializer Overview
Object Initializers allows the developer to create the
object instance and assign the initial values at the same
time.
The C# 2.0 way of initializing objects:
Customer cst2 = new Customer();
cst2.ID = 2;
cst2.Name = "Ayman Farouk";
cst2.Phone = "0799-987-980-98";
The C# 3.0 way of initializing objects:
Customer cst3 = new Customer()
{ ID = 3, Name = "Osama Salam", Phone = "074-545-545-67" };

7. Object and Collection Initializers
Collection Initializers Overview
The collection Initializers allows the developer to specify
one or more elements Initializers when initializing any
type that implements the System.Collections.Generic.IEnumerable<T>.
Initializers Rules:
1. Object Initializers cannot include more than one member initializer
for the same field or property.
2. The Object Initializers cannot refer to the newly created object it is
initializing.
3. The Collection type must implements
System.Collections.Generic.IEnumerable<T> in order to have
initializers.

8. Lab 2: Using Initializers
Writing Object Initializer expressions.
Writing Collection Initializer expressions.
Using the nested object initializer.
Using Initializers with multi-framework
versions.
Examining the generated initialization
instructions in the intermediate language.

9. Implicit Typing
Implicit Typing Overview
The new keyword var allows the C# compiler to infers
the type of variables
the compiler will determines the appropriate CLR type
Var differ than variant keyword in VB6 and COM
Implicit Typing Context:
1. Declaring variable at the method/property scope
2. In a for loop statement.
3. In a foreach loop statement.
4. In a using statement.

10. Lab 3: Using Implicit Typing
Using implicit-typed variables.
Using implicit typing with foreach context.
Using implicit typing with custom classes
and lists.
Using Implicit Typing with multi-
framework versions.
Examining the types of the implicit-typed
variables.

11. Extension Methods
Extension Methods Overview
Extension Methods allows the developer to inject new
methods to the existing compiled types without the need
to re-write or override the current implementations.
Extension Methods are natively supported in the VS
2008 IDE.
Defining Extension Methods:
1. Must be defined in separated static class.
2. Must be declared as static methods.
3. The first parameter modifier of the extension methods must be this
keyword.

12. Lab 4: Using Extension Methods
Extending types with extension methods.
Consuming extension methods.
Extending different .NET Framework built-
in types.

13. Lambda Expressions
Lambda Expressions Overview
Lambda expressions allows the developer to write
functions in expression context instead of writing it the
regular method body with a name.
it consists of two sides separated by the lambda
operator => “goes to”
the left side specifies the parameters if any, and the
right side holds the statement block or the expression.
Lambda Expression Limitation:
1. It can be only used as a part of statement.
2. The lambda expression does not have a name.
3. Lambda expression cannot contain a goto, break, or continue
statement whose target is outside the body.

14. Lab 5: Writing Expression Methods
Writing lambda expressions
Using the Lambda expressions.
Understanding the different in writing
expressions using delegates, anonymous
methods, and lambda expressions.

15. Review
In this module, you learned to:
Examine the Auto Properties Feature
Work with Initializers
Use the Implicit Typing Feature
Extending Existing Types
Writing Lambda Expressions