Tutorial by Examples: g

The finally { ... } block of a try-finally or try-catch-finally will always execute, regardless of whether an exception occurred or not (except when a StackOverflowException has been thrown or call has been made to Environment.FailFast()). It can be utilized to free or clean up resources acquired i...

var persons = new[] { new {Id = 1, Name = "Foo"}, new {Id = 2, Name = "Bar"}, new {Id = 3, Name = "Fizz"}, new {Id = 4, Name = "Buzz"} }; var personsSortedByNameDescending = persons.OrderByDescending(p => p.Name); Console.WriteL...

var oneNumber = new[] {5}; var theOnlyNumber = oneNumber.Single(); Console.WriteLine(theOnlyNumber); //5 var numbers = new[] {1,2,3,4,5}; var theOnlyNumberSmallerThanTwo = numbers.Single(n => n < 2); Console.WriteLine(theOnlyNumberSmallerThanTwo); //1 The following throws Invalid...

var oneNumber = new[] {5}; var theOnlyNumber = oneNumber.SingleOrDefault(); Console.WriteLine(theOnlyNumber); //5 var numbers = new[] {1,2,3,4,5}; var theOnlyNumberSmallerThanTwo = numbers.SingleOrDefault(n => n < 2); Console.WriteLine(theOnlyNumberSmallerThanTwo); //1 var theOnl...

var numbers = new[] {1,2,3,4}; var averageNumber = numbers.Average(); Console.WriteLine(averageNumber); // 2,5 This method calculates the average of enumerable of numbers. var cities = new[] { new {Population = 1000}, new {Population = 2000}, new {Population = 4000} }; v...

var persons = new[] { new { Name="Fizz", Job="Developer"}, new { Name="Buzz", Job="Developer"}, new { Name="Foo", Job="Astronaut"}, new { Name="Bar", Job="Astronaut"}, }; var groupedByJob = person...

Generating a new object in each step: var elements = new[] {1,2,3,4,5}; var commaSeparatedElements = elements.Aggregate( seed: "", func: (aggregate, element) => $"{aggregate}{element},"); Console.WriteLine(commaSeparatedElements); //1,2,3,4,5, Using th...

class Developer { public int Id { get; set; } public string Name { get; set; } } class Project { public int DeveloperId { get; set; } public string Name { get; set; } } var developers = new[] { new Developer { Id = 1, Name = "Foobuzz" ...

public interface IAnimal { string Name { get; set; } } public interface INoiseMaker { string MakeNoise(); } public class Cat : IAnimal, INoiseMaker { public Cat() { Name = "Cat"; } public string Name { get; set; } public string M...

public class LivingBeing { string Name { get; set; } } public interface IAnimal { bool HasHair { get; set; } } public interface INoiseMaker { string MakeNoise(); } //Note that in C#, the base class name must come before the interface names public class Cat : LivingBei...

interface BaseInterface {} class BaseClass : BaseInterface {} interface DerivedInterface {} class DerivedClass : BaseClass, DerivedInterface {} var baseInterfaceType = typeof(BaseInterface); var derivedInterfaceType = typeof(DerivedInterface); var baseType = typeof(BaseClass); var derived...

using System; using BasicStuff = System; using Sayer = System.Console; using static System.Console; //From C# 6 class Program { public static void Main() { System.Console.WriteLine("Ignoring usings and specifying full type name"); Console.WriteLine(&quot...

Using the null-coalescing operator (??) allows you to specify a default value for a nullable type if the left-hand operand is null. string testString = null; Console.WriteLine("The specified string is - " + (testString ?? "not provided")); Live Demo on .NET Fiddle This is l...

using is syntactic sugar that allows you to guarantee that a resource is cleaned up without needing an explicit try-finally block. This means your code will be much cleaner, and you won't leak non-managed resources. Standard Dispose cleanup pattern, for objects that implement the IDisposable interf...

The using static [Namespace.Type] directive allows the importing of static members of types and enumeration values. Extension methods are imported as extension methods (from just one type), not into top-level scope. 6.0 using static System.Console; using static System.ConsoleColor; using static ...

Overloading just equality operators is not enough. Under different circumstances, all of the following can be called: object.Equals and object.GetHashCode IEquatable<T>.Equals (optional, allows avoiding boxing) operator == and operator != (optional, allows using operators) When overrid...

Extension methods are static methods which behave like instance methods. However, unlike what happens when calling an instance method on a null reference, when an extension method is called with a null reference, it does not throw a NullReferenceException. This can be quite useful in some scenarios....

Apostrophes char apostrophe = '\''; Backslash char oneBackslash = '\\';

Backslash // The filename will be c:\myfile.txt in both cases string filename = "c:\\myfile.txt"; string filename = @"c:\myfile.txt"; The second example uses a verbatim string literal, which doesn't treat the backslash as an escape character. Quotes string text = "\&...

try { /* code that could throw an exception */ } catch (Exception ex) { /* handle the exception */ } Note that handling all exceptions with the same code is often not the best approach. This is commonly used when any inner exception handling routines fail, as a last resort.