C_Sharp_Language

C Sharp TutorialC Sharp .NET Compiler Platform (Roslyn)C Sharp 3.0 FeaturesC Sharp 4.0 FeaturesC Sharp 5.0 FeaturesC Sharp 6.0 FeaturesC Sharp 7.0 FeaturesC Sharp Access ModifiersC Sharp Access network shared folder with username and passwordC Sharp Accessing DatabasesC Sharp Action FiltersC Sharp Aliases of built-in typesC Sharp an overview of collectionsC Sharp Anonymous typesC Sharp ArraysC Sharp ASP.NET IdentityC Sharp AssemblyInfo.cs ExamplesC Sharp Async-AwaitC Sharp Async/await, Backgroundworker, Task and Thread ExamplesC Sharp Asynchronous SocketC Sharp AttributesC Sharp Authentication handlerC Sharp BackgroundWorkerC Sharp BigIntegerC Sharp Binary SerializationC Sharp BindingListC Sharp Built-in TypesC Sharp CachingC Sharp CastingC Sharp Checked and UncheckedC Sharp CLSCompliantAttributeC Sharp Code ContractsC Sharp Code Contracts and AssertionsC Sharp Collection InitializersC Sharp Comments and regionsC Sharp Common String OperationsC Sharp Conditional StatementsC Sharp Constructors and FinalizersC Sharp Creating Own MessageBox in Windows Form ApplicationC Sharp Creational Design PatternsC Sharp Cryptography (System.Security.Cryptography)C Sharp Data AnnotationC Sharp DateTime MethodsC Sharp DelegatesC Sharp Dependency InjectionC Sharp DiagnosticsC Sharp Dynamic typeC Sharp EnumC Sharp Equality OperatorC Sharp Equals and GetHashCodeC Sharp EventsC Sharp Exception HandlingC Sharp Expression TreesC Sharp Extension MethodsC Sharp File and Stream I/OC Sharp FileSystemWatcherC Sharp Func delegatesC Sharp Function with multiple return valuesC Sharp Functional ProgrammingC Sharp Garbage Collector in .NETC Sharp Generating Random NumbersC Sharp Generic Lambda Query BuilderC Sharp GenericsC Sharp Getting Started: Json with C SharpC Sharp GuidC Sharp Handling FormatException when converting string to other typesC Sharp Hash FunctionsC Sharp ICloneableC Sharp IComparableC Sharp IDisposable interfaceC Sharp IEnumerableC Sharp ILGeneratorC Sharp ImmutabilityC Sharp Implementing Decorator Design PatternC Sharp Implementing Flyweight Design PatternC Sharp Import Google ContactsC Sharp Including Font ResourcesC Sharp IndexerC Sharp InheritanceC Sharp Initializing PropertiesC Sharp INotifyPropertyChanged interfaceC Sharp InterfacesC Sharp InteroperabilityC Sharp IQueryable interfaceC Sharp IteratorsC Sharp KeywordsC Sharp Lambda expressionsC Sharp Lambda ExpressionsC Sharp LINQ QueriesC Sharp LINQ to Objects



C Sharp Equality Operator

From WikiOD

Equality kinds in c# and equality operator[edit | edit source]

In C#, there are two different kinds of equality: reference equality and value equality. Value equality is the commonly understood meaning of equality: it means that two objects contain the same values. For example, two integers with the value of 2 have value equality. Reference equality means that there are not two objects to compare. Instead, there are two object references, both of which refer to the same object.

object a = new object();
object b = a;
System.Object.ReferenceEquals(a, b);  //returns true

For predefined value types, the equality operator (==) returns true if the values of its operands are equal, false otherwise. For reference types other than string, == returns true if its two operands refer to the same object. For the string type, == compares the values of the strings.

// Numeric equality: True
Console.WriteLine((2 + 2) == 4);

// Reference equality: different objects, 
// same boxed value: False.
object s = 1;
object t = 1;
Console.WriteLine(s == t);

// Define some strings:
string a = "hello";
string b = String.Copy(a);
string c = "hello";

// Compare string values of a constant and an instance: True
Console.WriteLine(a == b);

// Compare string references; 
// a is a constant but b is an instance: False.
Console.WriteLine((object)a == (object)b);

// Compare string references, both constants 
// have the same value, so string interning
// points to same reference: True.
Console.WriteLine((object)a == (object)c);

Credit:Stack_Overflow_Documentation