Developing Windows and Web Applications using Visual Studio.NET

Peter Gfader

Who did the C# tutorial?

What is .NET?

What is the .NET framework?

What is the CLR?

What is OOP?

Session 1: Last week

Agenda

C# 3.0 Language Enhancement

C# 4.0 Language Enhancement

C# 5

What is LINQ?

LINQ Project Goals

LINQ Project Architecture

Data Binding via LINQ

Session 2: Overview

C# 32008

Local Variable Type Interface

Anonymous Type

Lambda Expressions

Extension methods

Object initializers

Query Expressions

C# 3.0 Language Enhancement

Local Variable Type Inference

Fits with complex temporarily variables

E.g. I want a temp variable to hold username & password

Anonymous Type

Anonymous methods in C#2

NumericalOperation mul1 = (x, y) => x * y;

Console.WriteLine( mul1(4, 5) );

Lambda Expressions

Extend every class with a static „helper“ method

Extension methods

More

Object initializer’s

Query Expressions

Please visit:

HookedOnLINQ.com

C# 4April 2010

„dynamic“ keyword

Optional parameters

Named parameters

Co and Contra variance

C# 4 Language Enhancement

Co and Contra varianceHow are generic types “broken” today?

var sheep = new List<Sheep>(); Speak(sheep);

void Speak(IEnumerable<Animal> animals) { // Do something with Animals }

class Animal { } class Sheep : Animal { }

Not Allowed:IEnumerable<Animal> != IEnumerable<Sheep>

Covariance – think “out”

Contravariance – think “in”

Break it down…

C# 5????? 2013 ????

„Meta programming is painful”

Compiler as a service

C# 5 ? - Release date?

Auto Implemented Properties

Collection Initializers

Named parameters

Optional parameters

Lambdas

Can span statements across multiple lines

Auto Implemented Properties

Collection Initializers (limited)

Named parameters

Optional parameters

Lambdas (limited)

Can span statements across multiple lines

.NET 3.5

Auto Implemented Properties

Collection Initializers

Named parameters

Optional parameters

Lambdas

Can span statements across multiple lines

Auto Implemented Properties

Collection Initializers

Named parameters

Optional parameters

Lambdas

Can span statements across multiple lines

.NET 4

Data accessShow me the data!

The problem

Problem

First showcased at the American International Toy Fair in New York in 2005

LINQ, a clever bluffing game

What is LINQ?

Language INtegrated Query

Allows you to easily query information about an object

LINQ to SQL: An ORM made by Microsoft LINQ to Entities: Another ORM made by Microsoft LINQ to XML: Query over XML ...

What is LINQ?

Language syntax+ a library of extension methods+ lambda expressions+ anonymous types+ a little magic

What is LINQ?

.NET Framework 3.5

LINQ is a natural language extension, part of .NET 3.5

Different data sources are queried with the same syntax.

Queries are strongly typed

Queries benefit from “Intellisense”

Applications becomes less error prone

LINQ - How does it solve the problem?

Unified programming model for any data type

Database Relational Data XML Files Collections & Arrays

Introduce more declarative syntax

Helps the system find the best execution strategy

LINQ Project Goals

LINQ Enabled Data Sources

LINQ Enabled ADO.NET

C# VB Others...

.NET Language Integrated Query (LINQ)

LINQ to

Objects

LINQ to Dataset

s

LINQ to

SQL

LINQ to

Entities

LINQ to

XML

LINQ to ??

?

<book> <title>

<author/> <price

/> </title></book>

Objects Database XML

LINQ Project Architecture

LINQ Query

string strSQL = “SELECT custID FROM Customers“;

SqlCommand cmd = new SqlCommand(strSQL, cnn);

SqlDataAdapter adAdapter = new SqlDataAdapter(cmd);

DataSet dst = new DataSet();

adAdapter.Fill(dst);

Standard Data Access Code

NorthwindDataContext db = new NorthwindDataContext();

var customers = from c in db.Customers

select c;

Code by LINQ

How to use LINQ

Benefits from LINQ

LINQ data binding

LINQ

Stored procedures are easier to work with

Relationship editor UI is nicer (more like SQL Server)

Performance

In a recent benchmark LINQ to SQL performed 5 times faster than LINQ to Entities

LINQ 2 SQL

More refined ORM than LINQ to SQL

Many to Many relationships

Richer support for Inheritance

Validation

Update model from database

Mapping Editor

LINQ 2 Entities

Do you know why you should choose "LINQ to Entities" over "LINQ to SQL"?

http://www.ssw.com.au/ssw/Standards/Rules/RulesToBetterLINQ.aspx#WhyLINQtoEntitiesNotSQL

What to choose?

LINQ Pad

http://www.linqpad.net/

Hot Tip

New features in C# 3.0

New features in C# 4.0

What is LINQ and Why LINQ

LINQ data binding

Summary

Introduction to LINQ http://msdn.microsoft.com/en-us/library/bb397897.aspx

Getting Started with LINQ in C# http://msdn.microsoft.com/en-us/library/bb397933.aspx

LINQ Term and more details http://www.hookedonlinq.com/

LinqPad http://www.linqpad.net/

Resources

What's next?

Thank You!

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