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authorLucas Pugliesi <ferreiraplucas@gmail.com>2017-10-05 08:55:34 -0300
committerLucas Pugliesi <ferreiraplucas@gmail.com>2017-10-05 08:55:34 -0300
commitd66603dd53083cb40f9eb94568c0538b6a03822e (patch)
tree8df8da3318b0fa14c2184d67627a4b77d55ff711 /pt-br/csharp-pt.html.markdown
parent31b9d9b8035ffe8581981e546b724ca6f3fc67d7 (diff)
parentccaa6ce57be4c2b972cdab36da28cbf603524bb2 (diff)
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+---
+language: c#
+filename: csharp-pt.cs
+contributors:
+ - ["Robson Alves", "http://robsonalves.net/"]
+lang: pt-br
+---
+
+C# é uma linguagem elegante e altamente tipado orientada a objetos que permite aos desenvolvedores criarem uma variedade de aplicações seguras e robustas que são executadas no .NET Framework.
+
+[Read more here.](http://msdn.microsoft.com/pt-br/library/vstudio/z1zx9t92.aspx)
+
+```c#
+// Comentário de linha única começa com //
+/*
+Múltipas linhas é desta forma
+*/
+/// <summary>
+/// Esta é uma documentação comentário XML que pode ser usado para gerar externo
+/// documentação ou fornecer ajuda de contexto dentro de um IDE
+/// </summary>
+//public void MethodOrClassOrOtherWithParsableHelp() {}
+
+// Especificar qual namespace seu código irá usar
+// Os namespaces a seguir são padrões do .NET Framework Class Library
+using System;
+using System.Collections.Generic;
+using System.Dynamic;
+using System.Linq;
+using System.Net;
+using System.Threading.Tasks;
+using System.IO;
+
+// Mas este aqui não é :
+using System.Data.Entity;
+// Para que consiga utiliza-lo, você precisa adicionar novas referências
+// Isso pode ser feito com o gerenciador de pacotes NuGet : `Install-Package EntityFramework`
+
+// Namespaces são escopos definidos para organizar o códgo em "pacotes" or "módulos"
+// Usando este código a partir de outra arquivo de origem: using Learning.CSharp;
+namespace Learning.CSharp
+{
+ // Cada .cs deve conter uma classe com o mesmo nome do arquivo
+ // você está autorizado a contrariar isto, mas evite por sua sanidade.
+ public class AprenderCsharp
+ {
+ // Sintaxe Básica - Pule para as CARACTERÍSTICAS INTERESSANTES se você ja usou Java ou C++ antes.
+ public static void Syntax()
+ {
+ // Use Console.WriteLine para apresentar uma linha
+ Console.WriteLine("Hello World");
+ Console.WriteLine(
+ "Integer: " + 10 +
+ " Double: " + 3.14 +
+ " Boolean: " + true);
+
+ // Para apresentar sem incluir uma nova linha, use Console.Write
+ Console.Write("Hello ");
+ Console.Write("World");
+
+ ///////////////////////////////////////////////////
+ // Tpos e Variáveis
+ //
+ // Declare uma variável usando <tipo> <nome>
+ ///////////////////////////////////////////////////
+
+ // Sbyte - Signed 8-bit integer
+ // (-128 <= sbyte <= 127)
+ sbyte fooSbyte = 100;
+
+ // Byte - Unsigned 8-bit integer
+ // (0 <= byte <= 255)
+ byte fooByte = 100;
+
+ // Short - 16-bit integer
+ // Signed - (-32,768 <= short <= 32,767)
+ // Unsigned - (0 <= ushort <= 65,535)
+ short fooShort = 10000;
+ ushort fooUshort = 10000;
+
+ // Integer - 32-bit integer
+ int fooInt = 1; // (-2,147,483,648 <= int <= 2,147,483,647)
+ uint fooUint = 1; // (0 <= uint <= 4,294,967,295)
+
+ // Long - 64-bit integer
+ long fooLong = 100000L; // (-9,223,372,036,854,775,808 <= long <= 9,223,372,036,854,775,807)
+ ulong fooUlong = 100000L; // (0 <= ulong <= 18,446,744,073,709,551,615)
+ // Numbers default to being int or uint depending on size.
+ // L is used to denote that this variable value is of type long or ulong
+
+ // Double - Double-precision 64-bit IEEE 754 Floating Point
+ double fooDouble = 123.4; // Precision: 15-16 digits
+
+ // Float - Single-precision 32-bit IEEE 754 Floating Point
+ float fooFloat = 234.5f; // Precision: 7 digits
+ // f is used to denote that this variable value is of type float
+
+ // Decimal - a 128-bits data type, with more precision than other floating-point types,
+ // suited for financial and monetary calculations
+ decimal fooDecimal = 150.3m;
+
+ // Boolean - true & false
+ bool fooBoolean = true; // or false
+
+ // Char - A single 16-bit Unicode character
+ char fooChar = 'A';
+
+ // Strings - ao contrário dos anteriores tipos base, que são todos os tipos de valor,
+            // Uma string é um tipo de referência. Ou seja, você pode configurá-lo como nulo
+ string fooString = "\"escape\" quotes and add \n (new lines) and \t (tabs)";
+ Console.WriteLine(fooString);
+
+ // Você pode acessar todos os caracteres de string com um indexador:
+ char charFromString = fooString[1]; // => 'e'
+ // Strings são imutáveis: você não pode fazer fooString[1] = 'X';
+
+ // Compare strings com sua atual cultura, ignorando maiúsculas e minúsculas
+ string.Compare(fooString, "x", StringComparison.CurrentCultureIgnoreCase);
+
+ // Formatando, baseado no sprintf
+ string fooFs = string.Format("Check Check, {0} {1}, {0} {1:0.0}", 1, 2);
+
+ // Datas e formatações
+ DateTime fooDate = DateTime.Now;
+ Console.WriteLine(fooDate.ToString("hh:mm, dd MMM yyyy"));
+
+ // Você pode juntar um string em mais de duas linhas com o símbolo @. Para escapar do " use ""
+ string bazString = @"Here's some stuff
+on a new line! ""Wow!"", the masses cried";
+
+ // Use const ou read-only para fazer uma variável imutável
+ // os valores da const são calculados durante o tempo de compilação
+ const int HoursWorkPerWeek = 9001;
+
+ ///////////////////////////////////////////////////
+ // Estrutura de Dados
+ ///////////////////////////////////////////////////
+
+ // Matrizes - zero indexado
+ // O tamanho do array pode ser decidido ainda na declaração
+ // O formato para declarar uma matriz é o seguinte:
+ // <tipodado>[] <var nome> = new <tipodado>[<array tamanho>];
+ int[] intArray = new int[10];
+
+ // Outra forma de declarar & inicializar uma matriz
+ int[] y = { 9000, 1000, 1337 };
+
+ // Indexando uma matriz - Acessando um elemento
+ Console.WriteLine("intArray @ 0: " + intArray[0]);
+ // Matriz são alteráveis
+ intArray[1] = 1;
+
+ // Listas
+ // Listas são usadas frequentemente tanto quanto matriz por serem mais flexiveis
+ // O formato de declarar uma lista é o seguinte:
+ // List<tipodado> <var nome> = new List<tipodado>();
+ List<int> intList = new List<int>();
+ List<string> stringList = new List<string>();
+ List<int> z = new List<int> { 9000, 1000, 1337 }; // inicializar
+ // O <> são para genéricos - Confira está interessante seção do material
+
+ // Lista não possuem valores padrão.
+ // Um valor deve ser adicionado antes e depois acessado pelo indexador
+ intList.Add(1);
+ Console.WriteLine("intList @ 0: " + intList[0]);
+
+ // Outras estruturas de dados para conferir:
+ // Pilha/Fila
+ // Dicionário (uma implementação de map de hash)
+ // HashSet
+ // Read-only Coleção
+ // Tuple (.Net 4+)
+
+ ///////////////////////////////////////
+ // Operadores
+ ///////////////////////////////////////
+ Console.WriteLine("\n->Operators");
+
+ int i1 = 1, i2 = 2; // Forma curta para declarar diversas variáveis
+
+ // Aritmética é clara
+ Console.WriteLine(i1 + i2 - i1 * 3 / 7); // => 3
+
+ // Modulo
+ Console.WriteLine("11%3 = " + (11 % 3)); // => 2
+
+ // Comparações de operadores
+ Console.WriteLine("3 == 2? " + (3 == 2)); // => falso
+ Console.WriteLine("3 != 2? " + (3 != 2)); // => verdadeiro
+ Console.WriteLine("3 > 2? " + (3 > 2)); // => verdadeiro
+ Console.WriteLine("3 < 2? " + (3 < 2)); // => falso
+ Console.WriteLine("2 <= 2? " + (2 <= 2)); // => verdadeiro
+ Console.WriteLine("2 >= 2? " + (2 >= 2)); // => verdadeiro
+
+ // Operadores bit a bit (bitwise)
+ /*
+ ~ Unário bitwise complemento
+ << Signed left shift
+ >> Signed right shift
+ & Bitwise AND
+ ^ Bitwise exclusivo OR
+ | Bitwise inclusivo OR
+ */
+
+ // Incrementações
+ int i = 0;
+ Console.WriteLine("\n->Inc/Dec-rementation");
+ Console.WriteLine(i++); //i = 1. Post-Incrementation
+ Console.WriteLine(++i); //i = 2. Pre-Incrementation
+ Console.WriteLine(i--); //i = 1. Post-Decrementation
+ Console.WriteLine(--i); //i = 0. Pre-Decrementation
+
+ ///////////////////////////////////////
+ // Estrutura de Controle
+ ///////////////////////////////////////
+ Console.WriteLine("\n->Control Structures");
+
+ // Declaração if é como a linguagem C
+ int j = 10;
+ if (j == 10)
+ {
+ Console.WriteLine("I get printed");
+ }
+ else if (j > 10)
+ {
+ Console.WriteLine("I don't");
+ }
+ else
+ {
+ Console.WriteLine("I also don't");
+ }
+
+ // Operador Ternário
+ // Um simples if/else pode ser escrito da seguinte forma
+ // <condição> ? <verdadeiro> : <falso>
+ int toCompare = 17;
+ string isTrue = toCompare == 17 ? "True" : "False";
+
+ // While loop
+ int fooWhile = 0;
+ while (fooWhile < 100)
+ {
+ //Iterated 100 times, fooWhile 0->99
+ fooWhile++;
+ }
+
+ // Do While Loop
+ int fooDoWhile = 0;
+ do
+ {
+ // Inicia a interação 100 vezes, fooDoWhile 0->99
+ if (false)
+ continue; // pule a intereção atual para apróxima
+
+ fooDoWhile++;
+
+ if (fooDoWhile == 50)
+ break; // Interrompe o laço inteiro
+
+ } while (fooDoWhile < 100);
+
+ //estrutura de loop for => for(<declaração para começar>; <condicional>; <passos>)
+ for (int fooFor = 0; fooFor < 10; fooFor++)
+ {
+ //Iterado 10 vezes, fooFor 0->9
+ }
+
+ // For Each Loop
+ // Estrutura do foreach => foreach(<Tipo Iterador> <Nome do Iterador> in <enumerable>)
+ // O laço foreach percorre sobre qualquer objeto que implementa IEnumerable ou IEnumerable<T>
+ // Toda a coleção de tipos (Array, List, Dictionary...) no .Net framework
+ // implementa uma ou mais destas interfaces.
+ // (O ToCharArray() pode ser removido, por que uma string também implementa IEnumerable)
+ foreach (char character in "Hello World".ToCharArray())
+ {
+ //Iterated over all the characters in the string
+ }
+
+ // Switch Case
+ // Um switch funciona com os tipos de dados byte, short, char, e int.
+ // Isto também funcional com tipos enumeradors (discutidos em Tipos Enum),
+ // A classe String, and a few special classes that wrap
+ // tipos primitívos: Character, Byte, Short, and Integer.
+ int month = 3;
+ string monthString;
+ switch (month)
+ {
+ case 1:
+ monthString = "January";
+ break;
+ case 2:
+ monthString = "February";
+ break;
+ case 3:
+ monthString = "March";
+ break;
+ // You can assign more than one case to an action
+ // But you can't add an action without a break before another case
+ // (if you want to do this, you would have to explicitly add a goto case x
+ case 6:
+ case 7:
+ case 8:
+ monthString = "Summer time!!";
+ break;
+ default:
+ monthString = "Some other month";
+ break;
+ }
+
+ ///////////////////////////////////////
+ // Converting Data Types And Typecasting
+ ///////////////////////////////////////
+
+ // Converting data
+
+ // Convert String To Integer
+ // this will throw a FormatException on failure
+ int.Parse("123");//returns an integer version of "123"
+
+ // try parse will default to type default on failure
+ // in this case: 0
+ int tryInt;
+ if (int.TryParse("123", out tryInt)) // Function is boolean
+ Console.WriteLine(tryInt); // 123
+
+ // Convert Integer To String
+ // Convert class has a number of methods to facilitate conversions
+ Convert.ToString(123);
+ // or
+ tryInt.ToString();
+
+ // Casting
+ // Cast decimal 15 to a int
+ // and then implicitly cast to long
+ long x = (int) 15M;
+ }
+
+ ///////////////////////////////////////
+ // CLASSES - see definitions at end of file
+ ///////////////////////////////////////
+ public static void Classes()
+ {
+ // See Declaration of objects at end of file
+
+ // Use new to instantiate a class
+ Bicycle trek = new Bicycle();
+
+ // Call object methods
+ trek.SpeedUp(3); // You should always use setter and getter methods
+ trek.Cadence = 100;
+
+ // ToString is a convention to display the value of this Object.
+ Console.WriteLine("trek info: " + trek.Info());
+
+ // Instantiate a new Penny Farthing
+ PennyFarthing funbike = new PennyFarthing(1, 10);
+ Console.WriteLine("funbike info: " + funbike.Info());
+
+ Console.Read();
+ } // End main method
+
+ // CONSOLE ENTRY A console application must have a main method as an entry point
+ public static void Main(string[] args)
+ {
+ OtherInterestingFeatures();
+ }
+
+ //
+ // INTERESTING FEATURES
+ //
+
+ // DEFAULT METHOD SIGNATURES
+
+ public // Visibility
+ static // Allows for direct call on class without object
+ int // Return Type,
+ MethodSignatures(
+ int maxCount, // First variable, expects an int
+ int count = 0, // will default the value to 0 if not passed in
+ int another = 3,
+ params string[] otherParams // captures all other parameters passed to method
+ )
+ {
+ return -1;
+ }
+
+ // Methods can have the same name, as long as the signature is unique
+ // A method that differs only in return type is not unique
+ public static void MethodSignatures(
+ ref int maxCount, // Pass by reference
+ out int count)
+ {
+ count = 15; // out param must be assigned before control leaves the method
+ }
+
+ // GENERICS
+ // The classes for TKey and TValue is specified by the user calling this function.
+ // This method emulates the SetDefault of Python
+ public static TValue SetDefault<TKey, TValue>(
+ IDictionary<TKey, TValue> dictionary,
+ TKey key,
+ TValue defaultItem)
+ {
+ TValue result;
+ if (!dictionary.TryGetValue(key, out result))
+ return dictionary[key] = defaultItem;
+ return result;
+ }
+
+ // You can narrow down the objects that are passed in
+ public static void IterateAndPrint<T>(T toPrint) where T: IEnumerable<int>
+ {
+ // We can iterate, since T is a IEnumerable
+ foreach (var item in toPrint)
+ // Item is an int
+ Console.WriteLine(item.ToString());
+ }
+
+ public static void OtherInterestingFeatures()
+ {
+ // OPTIONAL PARAMETERS
+ MethodSignatures(3, 1, 3, "Some", "Extra", "Strings");
+ MethodSignatures(3, another: 3); // explicity set a parameter, skipping optional ones
+
+ // BY REF AND OUT PARAMETERS
+ int maxCount = 0, count; // ref params must have value
+ MethodSignatures(ref maxCount, out count);
+
+ // EXTENSION METHODS
+ int i = 3;
+ i.Print(); // Defined below
+
+ // NULLABLE TYPES - great for database interaction / return values
+ // any value type (i.e. not a class) can be made nullable by suffixing a ?
+ // <type>? <var name> = <value>
+ int? nullable = null; // short hand for Nullable<int>
+ Console.WriteLine("Nullable variable: " + nullable);
+ bool hasValue = nullable.HasValue; // true if not null
+
+ // ?? is syntactic sugar for specifying default value (coalesce)
+ // in case variable is null
+ int notNullable = nullable ?? 0; // 0
+
+ // IMPLICITLY TYPED VARIABLES - you can let the compiler work out what the type is:
+ var magic = "magic is a string, at compile time, so you still get type safety";
+ // magic = 9; will not work as magic is a string, not an int
+
+ // GENERICS
+ //
+ var phonebook = new Dictionary<string, string>() {
+ {"Sarah", "212 555 5555"} // Add some entries to the phone book
+ };
+
+ // Calling SETDEFAULT defined as a generic above
+ Console.WriteLine(SetDefault<string,string>(phonebook, "Shaun", "No Phone")); // No Phone
+ // nb, you don't need to specify the TKey and TValue since they can be
+ // derived implicitly
+ Console.WriteLine(SetDefault(phonebook, "Sarah", "No Phone")); // 212 555 5555
+
+ // LAMBDA EXPRESSIONS - allow you to write code in line
+ Func<int, int> square = (x) => x * x; // Last T item is the return value
+ Console.WriteLine(square(3)); // 9
+
+ // ERROR HANDLING - coping with an uncertain world
+ try
+ {
+ var funBike = PennyFarthing.CreateWithGears(6);
+
+ // will no longer execute because CreateWithGears throws an exception
+ string some = "";
+ if (true) some = null;
+ some.ToLower(); // throws a NullReferenceException
+ }
+ catch (NotSupportedException)
+ {
+ Console.WriteLine("Not so much fun now!");
+ }
+ catch (Exception ex) // catch all other exceptions
+ {
+ throw new ApplicationException("It hit the fan", ex);
+ // throw; // A rethrow that preserves the callstack
+ }
+ // catch { } // catch-all without capturing the Exception
+ finally
+ {
+ // executes after try or catch
+ }
+
+ // DISPOSABLE RESOURCES MANAGEMENT - let you handle unmanaged resources easily.
+ // Most of objects that access unmanaged resources (file handle, device contexts, etc.)
+ // implement the IDisposable interface. The using statement takes care of
+ // cleaning those IDisposable objects for you.
+ using (StreamWriter writer = new StreamWriter("log.txt"))
+ {
+ writer.WriteLine("Nothing suspicious here");
+ // At the end of scope, resources will be released.
+ // Even if an exception is thrown.
+ }
+
+ // PARALLEL FRAMEWORK
+ // http://blogs.msdn.com/b/csharpfaq/archive/2010/06/01/parallel-programming-in-net-framework-4-getting-started.aspx
+ var websites = new string[] {
+ "http://www.google.com", "http://www.reddit.com",
+ "http://www.shaunmccarthy.com"
+ };
+ var responses = new Dictionary<string, string>();
+
+ // Will spin up separate threads for each request, and join on them
+ // before going to the next step!
+ Parallel.ForEach(websites,
+ new ParallelOptions() {MaxDegreeOfParallelism = 3}, // max of 3 threads
+ website =>
+ {
+ // Do something that takes a long time on the file
+ using (var r = WebRequest.Create(new Uri(website)).GetResponse())
+ {
+ responses[website] = r.ContentType;
+ }
+ });
+
+ // This won't happen till after all requests have been completed
+ foreach (var key in responses.Keys)
+ Console.WriteLine("{0}:{1}", key, responses[key]);
+
+ // DYNAMIC OBJECTS (great for working with other languages)
+ dynamic student = new ExpandoObject();
+ student.FirstName = "First Name"; // No need to define class first!
+
+ // You can even add methods (returns a string, and takes in a string)
+ student.Introduce = new Func<string, string>(
+ (introduceTo) => string.Format("Hey {0}, this is {1}", student.FirstName, introduceTo));
+ Console.WriteLine(student.Introduce("Beth"));
+
+ // IQUERYABLE<T> - almost all collections implement this, which gives you a lot of
+ // very useful Map / Filter / Reduce style methods
+ var bikes = new List<Bicycle>();
+ bikes.Sort(); // Sorts the array
+ bikes.Sort((b1, b2) => b1.Wheels.CompareTo(b2.Wheels)); // Sorts based on wheels
+ var result = bikes
+ .Where(b => b.Wheels > 3) // Filters - chainable (returns IQueryable of previous type)
+ .Where(b => b.IsBroken && b.HasTassles)
+ .Select(b => b.ToString()); // Map - we only this selects, so result is a IQueryable<string>
+
+ var sum = bikes.Sum(b => b.Wheels); // Reduce - sums all the wheels in the collection
+
+ // Create a list of IMPLICIT objects based on some parameters of the bike
+ var bikeSummaries = bikes.Select(b=>new { Name = b.Name, IsAwesome = !b.IsBroken && b.HasTassles });
+ // Hard to show here, but you get type ahead completion since the compiler can implicitly work
+ // out the types above!
+ foreach (var bikeSummary in bikeSummaries.Where(b => b.IsAwesome))
+ Console.WriteLine(bikeSummary.Name);
+
+ // ASPARALLEL
+ // And this is where things get wicked - combines linq and parallel operations
+ var threeWheelers = bikes.AsParallel().Where(b => b.Wheels == 3).Select(b => b.Name);
+ // this will happen in parallel! Threads will automagically be spun up and the
+ // results divvied amongst them! Amazing for large datasets when you have lots of
+ // cores
+
+ // LINQ - maps a store to IQueryable<T> objects, with delayed execution
+ // e.g. LinqToSql - maps to a database, LinqToXml maps to an xml document
+ var db = new BikeRepository();
+
+ // execution is delayed, which is great when querying a database
+ var filter = db.Bikes.Where(b => b.HasTassles); // no query run
+ if (42 > 6) // You can keep adding filters, even conditionally - great for "advanced search" functionality
+ filter = filter.Where(b => b.IsBroken); // no query run
+
+ var query = filter
+ .OrderBy(b => b.Wheels)
+ .ThenBy(b => b.Name)
+ .Select(b => b.Name); // still no query run
+
+ // Now the query runs, but opens a reader, so only populates are you iterate through
+ foreach (string bike in query)
+ Console.WriteLine(result);
+
+
+
+ }
+
+ } // End LearnCSharp class
+
+ // You can include other classes in a .cs file
+
+ public static class Extensions
+ {
+ // EXTENSION FUNCTIONS
+ public static void Print(this object obj)
+ {
+ Console.WriteLine(obj.ToString());
+ }
+ }
+
+ // Class Declaration Syntax:
+ // <public/private/protected/internal> class <class name>{
+ // //data fields, constructors, functions all inside.
+ // //functions are called as methods in Java.
+ // }
+
+ public class Bicycle
+ {
+ // Bicycle's Fields/Variables
+ public int Cadence // Public: Can be accessed from anywhere
+ {
+ get // get - define a method to retrieve the property
+ {
+ return _cadence;
+ }
+ set // set - define a method to set a proprety
+ {
+ _cadence = value; // Value is the value passed in to the setter
+ }
+ }
+ private int _cadence;
+
+ protected virtual int Gear // Protected: Accessible from the class and subclasses
+ {
+ get; // creates an auto property so you don't need a member field
+ set;
+ }
+
+ internal int Wheels // Internal: Accessible from within the assembly
+ {
+ get;
+ private set; // You can set modifiers on the get/set methods
+ }
+
+ int _speed; // Everything is private by default: Only accessible from within this class.
+ // can also use keyword private
+ public string Name { get; set; }
+
+ // Enum is a value type that consists of a set of named constants
+ // It is really just mapping a name to a value (an int, unless specified otherwise).
+ // The approved types for an enum are byte, sbyte, short, ushort, int, uint, long, or ulong.
+ // An enum can't contain the same value twice.
+ public enum BikeBrand
+ {
+ AIST,
+ BMC,
+ Electra = 42, //you can explicitly set a value to a name
+ Gitane // 43
+ }
+ // We defined this type inside a Bicycle class, so it is a nested type
+ // Code outside of this class should reference this type as Bicycle.Brand
+
+ public BikeBrand Brand; // After declaring an enum type, we can declare the field of this type
+
+ // Decorate an enum with the FlagsAttribute to indicate that multiple values can be switched on
+ [Flags] // Any class derived from Attribute can be used to decorate types, methods, parameters etc
+ public enum BikeAccessories
+ {
+ None = 0,
+ Bell = 1,
+ MudGuards = 2, // need to set the values manually!
+ Racks = 4,
+ Lights = 8,
+ FullPackage = Bell | MudGuards | Racks | Lights
+ }
+
+ // Usage: aBike.Accessories.HasFlag(Bicycle.BikeAccessories.Bell)
+ // Before .NET 4: (aBike.Accessories & Bicycle.BikeAccessories.Bell) == Bicycle.BikeAccessories.Bell
+ public BikeAccessories Accessories { get; set; }
+
+ // Static members belong to the type itself rather then specific object.
+ // You can access them without a reference to any object:
+ // Console.WriteLine("Bicycles created: " + Bicycle.bicyclesCreated);
+ public static int BicyclesCreated { get; set; }
+
+ // readonly values are set at run time
+ // they can only be assigned upon declaration or in a constructor
+ readonly bool _hasCardsInSpokes = false; // read-only private
+
+ // Constructors are a way of creating classes
+ // This is a default constructor
+ public Bicycle()
+ {
+ this.Gear = 1; // you can access members of the object with the keyword this
+ Cadence = 50; // but you don't always need it
+ _speed = 5;
+ Name = "Bontrager";
+ Brand = BikeBrand.AIST;
+ BicyclesCreated++;
+ }
+
+ // This is a specified constructor (it contains arguments)
+ public Bicycle(int startCadence, int startSpeed, int startGear,
+ string name, bool hasCardsInSpokes, BikeBrand brand)
+ : base() // calls base first
+ {
+ Gear = startGear;
+ Cadence = startCadence;
+ _speed = startSpeed;
+ Name = name;
+ _hasCardsInSpokes = hasCardsInSpokes;
+ Brand = brand;
+ }
+
+ // Constructors can be chained
+ public Bicycle(int startCadence, int startSpeed, BikeBrand brand) :
+ this(startCadence, startSpeed, 0, "big wheels", true, brand)
+ {
+ }
+
+ // Function Syntax:
+ // <public/private/protected> <return type> <function name>(<args>)
+
+ // classes can implement getters and setters for their fields
+ // or they can implement properties (this is the preferred way in C#)
+
+ // Method parameters can have default values.
+ // In this case, methods can be called with these parameters omitted
+ public void SpeedUp(int increment = 1)
+ {
+ _speed += increment;
+ }
+
+ public void SlowDown(int decrement = 1)
+ {
+ _speed -= decrement;
+ }
+
+ // properties get/set values
+ // when only data needs to be accessed, consider using properties.
+ // properties may have either get or set, or both
+ private bool _hasTassles; // private variable
+ public bool HasTassles // public accessor
+ {
+ get { return _hasTassles; }
+ set { _hasTassles = value; }
+ }
+
+ // You can also define an automatic property in one line
+ // this syntax will create a backing field automatically.
+ // You can set an access modifier on either the getter or the setter (or both)
+ // to restrict its access:
+ public bool IsBroken { get; private set; }
+
+ // Properties can be auto-implemented
+ public int FrameSize
+ {
+ get;
+ // you are able to specify access modifiers for either get or set
+ // this means only Bicycle class can call set on Framesize
+ private set;
+ }
+
+ // It's also possible to define custom Indexers on objects.
+ // All though this is not entirely useful in this example, you
+ // could do bicycle[0] which yields "chris" to get the first passenger or
+ // bicycle[1] = "lisa" to set the passenger. (of this apparent quattrocycle)
+ private string[] passengers = { "chris", "phil", "darren", "regina" };
+
+ public string this[int i]
+ {
+ get {
+ return passengers[i];
+ }
+
+ set {
+ return passengers[i] = value;
+ }
+ }
+
+ //Method to display the attribute values of this Object.
+ public virtual string Info()
+ {
+ return "Gear: " + Gear +
+ " Cadence: " + Cadence +
+ " Speed: " + _speed +
+ " Name: " + Name +
+ " Cards in Spokes: " + (_hasCardsInSpokes ? "yes" : "no") +
+ "\n------------------------------\n"
+ ;
+ }
+
+ // Methods can also be static. It can be useful for helper methods
+ public static bool DidWeCreateEnoughBycles()
+ {
+ // Within a static method, we only can reference static class members
+ return BicyclesCreated > 9000;
+ } // If your class only needs static members, consider marking the class itself as static.
+
+
+ } // end class Bicycle
+
+ // PennyFarthing is a subclass of Bicycle
+ class PennyFarthing : Bicycle
+ {
+ // (Penny Farthings are those bicycles with the big front wheel.
+ // They have no gears.)
+
+ // calling parent constructor
+ public PennyFarthing(int startCadence, int startSpeed) :
+ base(startCadence, startSpeed, 0, "PennyFarthing", true, BikeBrand.Electra)
+ {
+ }
+
+ protected override int Gear
+ {
+ get
+ {
+ return 0;
+ }
+ set
+ {
+ throw new InvalidOperationException("You can't change gears on a PennyFarthing");
+ }
+ }
+
+ public static PennyFarthing CreateWithGears(int gears)
+ {
+ var penny = new PennyFarthing(1, 1);
+ penny.Gear = gears; // Oops, can't do this!
+ return penny;
+ }
+
+ public override string Info()
+ {
+ string result = "PennyFarthing bicycle ";
+ result += base.ToString(); // Calling the base version of the method
+ return result;
+ }
+ }
+
+ // Interfaces only contain signatures of the members, without the implementation.
+ interface IJumpable
+ {
+ void Jump(int meters); // all interface members are implicitly public
+ }
+
+ interface IBreakable
+ {
+ bool Broken { get; } // interfaces can contain properties as well as methods & events
+ }
+
+ // Class can inherit only one other class, but can implement any amount of interfaces
+ class MountainBike : Bicycle, IJumpable, IBreakable
+ {
+ int damage = 0;
+
+ public void Jump(int meters)
+ {
+ damage += meters;
+ }
+
+ public bool Broken
+ {
+ get
+ {
+ return damage > 100;
+ }
+ }
+ }
+
+ /// <summary>
+ /// Used to connect to DB for LinqToSql example.
+ /// EntityFramework Code First is awesome (similar to Ruby's ActiveRecord, but bidirectional)
+ /// http://msdn.microsoft.com/en-us/data/jj193542.aspx
+ /// </summary>
+ public class BikeRepository : DbContext
+ {
+ public BikeRepository()
+ : base()
+ {
+ }
+
+ public DbSet<Bicycle> Bikes { get; set; }
+ }
+} // End Namespace
+```
+
+## Topics Not Covered
+
+ * Attributes
+ * async/await, yield, pragma directives
+ * Web Development
+ * ASP.NET MVC & WebApi (new)
+ * ASP.NET Web Forms (old)
+ * WebMatrix (tool)
+ * Desktop Development
+ * Windows Presentation Foundation (WPF) (new)
+ * Winforms (old)
+
+## Further Reading
+
+ * [DotNetPerls](http://www.dotnetperls.com)
+ * [C# in Depth](http://manning.com/skeet2)
+ * [Programming C#](http://shop.oreilly.com/product/0636920024064.do)
+ * [LINQ](http://shop.oreilly.com/product/9780596519254.do)
+ * [MSDN Library](http://msdn.microsoft.com/en-us/library/618ayhy6.aspx)
+ * [ASP.NET MVC Tutorials](http://www.asp.net/mvc/tutorials)
+ * [ASP.NET Web Matrix Tutorials](http://www.asp.net/web-pages/tutorials)
+ * [ASP.NET Web Forms Tutorials](http://www.asp.net/web-forms/tutorials)
+ * [Windows Forms Programming in C#](http://www.amazon.com/Windows-Forms-Programming-Chris-Sells/dp/0321116208)
+ * [C# Coding Conventions](http://msdn.microsoft.com/en-us/library/vstudio/ff926074.aspx)