.NET Team.NET Team.NET Team.NET TeamLINQ & ADO.NET Entity FrameworkLINQ & ADO.NET Entity Framework

Stefan DobrevStefan DobrevGMGM

Avaxo Ltd.Avaxo Ltd.

http://ligaz.blogspot.com

ContentsContentsContentsContents

1.1. LINQ – general stuffLINQ – general stuff

2.2. LINQ ProvidersLINQ Providers

3.3. ADO.NET Entity FrameworkADO.NET Entity Framework

1.1. LINQ – general stuffLINQ – general stuff

2.2. LINQ ProvidersLINQ Providers

3.3. ADO.NET Entity FrameworkADO.NET Entity Framework

LINQLINQLINQLINQLanguage Integrated QueryLanguage Integrated Query

DEMODEMODEMODEMO

LINQ in ActionLINQ in ActionLINQ in ActionLINQ in Action

What we saw?What we saw?What we saw?What we saw?

varvar func = func = fromfrom l l inin ProgrammingLanguage.GetAll() ProgrammingLanguage.GetAll() wherewhere l.Paradigm.HasValue(Functional) l.Paradigm.HasValue(Functional) selectselect l; l;

varvar func = func = ProgrammingLanguage.GetAll()ProgrammingLanguage.GetAll() ..WhereWhere(l => l.Paradigm.HasValue(Functional))(l => l.Paradigm.HasValue(Functional)) ..SelectSelect(l => l);(l => l);

Query Query expressionsexpressions

Query Query expressionsexpressions

Local variable Local variable type inferencetype inferenceLocal variable Local variable type inferencetype inference

Extension Extension methodsmethods

Extension Extension methodsmethods

Lambda Lambda expressionexpression

ss

Lambda Lambda expressionexpression

ss

Expression Expression TreesTrees

Expression Expression TreesTrees

Local Variable Type InferenceLocal Variable Type InferenceLocal Variable Type InferenceLocal Variable Type Inference

int i = 5;int i = 5;string s = "Hello";string s = "Hello";double d = 1.0;double d = 1.0;int[] numbers = new int[] {1, 2, 3};int[] numbers = new int[] {1, 2, 3};Dictionary<int,Order> orders = new Dictionary<int,Order> orders = new Dictionary<int,Order>();Dictionary<int,Order>();

var i = 5;var i = 5;var s = "Hello";var s = "Hello";var d = 1.0;var d = 1.0;var numbers = new int[] {1, 2, 3};var numbers = new int[] {1, 2, 3};var orders = new var orders = new Dictionary<int,Order>();Dictionary<int,Order>();

Compiler infers the Compiler infers the correct type from the correct type from the

right sideright side

Compiler infers the Compiler infers the correct type from the correct type from the

right sideright side

Extension MethodsExtension MethodsExtension MethodsExtension Methods

namespacenamespace ITBoxing ITBoxing{{ public static classpublic static class Extensions Extensions {{ public static string public static string HasValue(HasValue( thisthis ProgrammingParadigm paradigm, ProgrammingParadigm paradigm, ProgrammingParadigm value ) ProgrammingParadigm value ) {{ returnreturn ( paradigm & value ) != 0 ( paradigm & value ) != 0 }} }}}}

Bring Bring extensions into extensions into

scopescope

Bring Bring extensions into extensions into

scopescopeusingusing ITBoxing ITBoxing

ProgrammingParadigm paradigm = Functional & Imperative;ProgrammingParadigm paradigm = Functional & Imperative;Paradigm.HasValue(Imperative);Paradigm.HasValue(Imperative);

obj.Foo(x, y)obj.Foo(x, y)

XXX.Foo(obj, x, y)XXX.Foo(obj, x, y)

obj.Foo(x, y)obj.Foo(x, y)

XXX.Foo(obj, x, y)XXX.Foo(obj, x, y)

IntelliSensIntelliSensee

IntelliSensIntelliSensee

Extension Extension MethodMethod

Extension Extension MethodMethod

Lambda ExpressionsLambda ExpressionsLambda ExpressionsLambda Expressions

List<ProgrammingLanguage> langs = List<ProgrammingLanguage> langs = ProgrammingLanguage.GetAll();ProgrammingLanguage.GetAll();List<ProgrammingLanguage> cool =List<ProgrammingLanguage> cool = langs.FindAll(langs.FindAll( delegatedelegate(ProgrammingLanguage l)(ProgrammingLanguage l) {{ returnreturn l.IsCool; l.IsCool; } } ););

List<ProgrammingLanguage> langs = List<ProgrammingLanguage> langs = ProgrammingLanguage.GetAll();ProgrammingLanguage.GetAll();List<ProgrammingLanguage> cool =List<ProgrammingLanguage> cool = langs.FindAll(l => l.IsCool);langs.FindAll(l => l.IsCool);

Lambda expressionLambda expressionLambda expressionLambda expression

Expression TreesExpression TreesExpression TreesExpression TreesCode as DataCode as Data

Expression<Predicate<ProgrammingLanguage>>Expression<Predicate<ProgrammingLanguage>> isCool = l => l.IsCool == true;isCool = l => l.IsCool == true;

public delegate bool public delegate bool Predicate<T>(T item);Predicate<T>(T item);

ParameterExpression l = ParameterExpression l = Expression.Parameter(Expression.Parameter( typeoftypeof(ProgrammingLanguage), "l" );(ProgrammingLanguage), "l" );

Expression expr = Expression expr = Expression.Equal(Expression.Equal( Expression.Property(l, Expression.Property(l, typeof(ProgrammingLanguage)typeof(ProgrammingLanguage) .GetProperty("IsCool")), .GetProperty("IsCool")), Expression.Constant(true));Expression.Constant(true)); Expression<PredicateExpression<Predicate<ProgrammingLanguage>> isCool = <ProgrammingLanguage>> isCool = Expression.LambdaExpression.Lambda <Predicate<ProgrammingLanguage>>(expr, l);<Predicate<ProgrammingLanguage>>(expr, l);

LINQ & LINQ & ADO.NET Entity FrameworkADO.NET Entity FrameworkLINQ & LINQ & ADO.NET Entity FrameworkADO.NET Entity Framework

Questions?Questions?Questions?Questions?