Cs30 New

C# 3.0 What’s new by Chakravarthy http://msmvps.com/blogs/chakravarthy [email_address] Project Lead

Agenda What’s new in Orcas C# 3.0 Implicit Variables Auto implemented properties Object & Collection Initializers Extension Methods Anonymous Types Lambda Expressions Generic Delegates Expression Trees Are we missing any thing here ?????

Pre-Requisites Some Programming Exp C C ++ .NET Basics Apart of all .. Imagination is more important than knowledge .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

Ur acquaintance with C# Using it more than 2 Yrs Started Recently Am new to C# What C# is ..?

Orcas What is ? Specialisation doesn’t mean doing extraordinary things But doing ordinary things, extraordinarily well..

Visual Studio Code Name – Orcas Web Multi version apps CSS Design tools Intellisense for ECMA Script AJAX Library Applications Templates WPF WCF WF Data Integration EDM – Entity Data Manager (ADO.NET vNext) Multi-tier Dataset Reporting Project templates

demo Visual Studio Code name Orcas Ctrl+Tab MultiVersion ECMA Intellisupport DataIntegration(EDM) AJAX Support CSS

C# 3.0 Features If we fail to plan, we are planning to fail

Agenda What’s new in Orcas C# 3.0 Implicit Variables Auto implemented properties Object & Collection Initializers Extension Methods Anonymous Types / Tuples Lambda Expressions Generic Delegates (Func) Expression Methods Partial Methods

Implicitly typed local variables Declared as ‘var’ – compiler will determine type while initialization Can only be used when declared and initialized in same statement Can’t be null Can’t be class members Used to store anonymous types as in LINQ based programming Don’t confuse with “var” at JavaScript or VB, which actually allows you to assign any type to a variable in your code Multiple declarations should evaluate at Compile time var bVal = true; var strVal = “MATUG”; Var intNum = 9; var obj = new { UGName = “Automated Test”, url = “http://matug.net”, alturl =“http://groups.msn.com/matug/”}

Implicitly typed arrays Declared as ‘var’ – compiler will determine type while initialization Collection type of elements is determined by compiler var fstArry = new[] {3,6,11,78,93};  Int32 var secArry = new[] {3,6,11.48,78,93};  Double var thrArry = new[] {“Microsoft”, “MAQ”};  String var secArry = new[] {3,6,11.48,”78”,93};  Won’t compile due to irregularity in the elements

demo Implicit Variables Variables Multiple Declaration Typed Arrays Arrays Mismatch

Auto implemented properties Compiler will create the private variables Single line public property accessor Simple object persistence mechanism Old Style private string strVar; public string EmployeeName { get{return strVar;} set{strVar = value;} } C# 3.0 public string EmployeeName { get; set; } Would you like to know what happens behind the screen ?

Auto implemented properties Assembler will give you the code similar to the below namespace SampleLib { public class YesClass { // Fields [ CompilerGenerated ] private string <>k__AutomaticallyGeneratedPropertyField0 ; // Methods public YesClass (); public void DoNothing (); // Properties public string Reply { [ CompilerGenerated ] get; [ CompilerGenerated ] set; } } } How do you know this ? … Use any Reflector ..

demo Property Property Reflector

Object & Collection Initializers Declaration and initialization at one step Ease of construction and initialization process Sequence of members are separated by ‘,’ Should be an accessible field assigned with = operator

demo Object & Collections Object from a class Collections from a List <>

Extension Methods Static Methods Invoked with instance method syntax Declared by “this” keyword as modifier Declared in “static” classes only Extension members of other kinds, such as properties, events, and operators, are being considered but are currently not supported.

demo Extension Methods Reverse the given string

Anonymous Types No class code declaration Direct initialization Type is omitted at syntax Not only the variables but objects can also be anonymous Old Style public class Book { … } Book bkObj = new Book(); C# 3.0 Style var bkObj = new { Title = “Harry Potter 7”, PubYr = 2007}

Agenda What’s new in Orcas C# 3.0 Implicit Variables Auto implemented properties Object & Collection Initializers Extension Methods Anonymous Types / Tuples Lambda Expressions Generic Delegates (Func) Expression Methods Partial Methods Did I miss something???

λ Lambda Expressions Extension of anonymous methods Advancement of Delegates Is an inline expression / statement block with a concise syntax that can be used wherever a delegate or anonymous method is expected which can be used to pass arguments to method call or assign value to delegate Expression use “=>” operator Left side denotes result Right side contains statement block or expression

Lambda Expressions // Data source. int[] Scores = { 90, 71, 82, 93, 75, 82 }; Write me some code that returns me the count for the numbers that are greater than 80 ? // This query executes immediately because it returns a singleton int value, not an iterable sequence. int scoreQuery = Scores.Where(n => n > 80).Count();

Lambda Expressions // Data source. string[] Projects = { “eZCap”, “iMedsoft”, “Patient Portal”, “LiveWellHRA”, “ETL”, “iMedLiveWell”}; Write me some code that returns me the projects that has “Med” in project name ? IEnumerable<string> projsQry = from proj in projs where proj.Contains("Med") select proj; foreach (string projName in projsQry) { Console.WriteLine(projName); }

λ Lambda Expressions – conti .. Improved type inference Conversion for both delegate types as well as expression trees Expression trees ?? Lambda expressions with an expression body can be converted to expression tree General rules Must contain same number of parameters as the delegate type Each parameter and return value must be implicitly convertible to its corresponding delegate parameter or delegate return type

demo Lambda Expressions Delegates Anonymous Methods Lambda Expressions

Generic Delegates (Func) Allows to construct a method with out declaring delegate 5 predefined generic delegates Last parameter is always return type You can extend them with LINQ Func<>

demo Generic Delegates Func<string, string>

Agenda What’s new in Orcas C# 3.0 Implicit Variables Auto implemented properties Object & Collection Initializers Extension Methods Anonymous Types / Tuples Lambda Expressions Generic Delegates (Func) Expression Trees Partial Methods

Expression Trees Don’t get confuse System.LINQ.Expression with Windows.Forms Allow lamda expressions as data instead of code Expression<>

demo Expression Trees Expression<Func<string, string>> Expression.Compile

For further win/win var WhoIsThereNextMonth = new { Default = “Chakravarthy”, Perhaps = “Sarma & Siva”, AreYou =“NotSure”, Topics =“What do you Want ??”, AnyThing =“Don’t hesitate, ASK ME” }

Where to go for any technical Post your message at http:// groups.msn.com/CSharpGroup Drop me a line at chakravarthy.dsk@inteq Visit our sessions on “KS” Knowledge Share with out fail

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