Tutorial by Examples: p

var tasks = Enumerable.Range(1, 5).Select(n => new Task<int>(() => { Console.WriteLine("I'm task " + n); return n; })).ToArray(); foreach(var task in tasks) task.Start(); Task.WaitAll(tasks); foreach(var task in tasks) Console.WriteLine(task.Result); ...

var task1 = Task.Run(() => { Console.WriteLine("Task 1 code starting..."); throw new Exception("Oh no, exception from task 1!!"); }); var task2 = Task.Run(() => { Console.WriteLine("Task 2 code starting..."); throw new Exception("Oh ...

var task1 = Task.Run(() => { Console.WriteLine("Task 1 code starting..."); throw new Exception("Oh no, exception from task 1!!"); }); var task2 = Task.Run(() => { Console.WriteLine("Task 2 code starting..."); throw new Exception("Oh ...

var actions = Enumerable.Range(1, 10).Select(n => new Action(() => { Console.WriteLine("I'm task " + n); if((n & 1) == 0) throw new Exception("Exception from task " + n); })).ToArray(); try { Parallel.Invoke(actions); } catch(AggregateExc...

var dateString = "2015-11-24"; var date = DateTime.ParseExact(dateString, "yyyy-MM-dd", null); Console.WriteLine(date); 11/24/2015 12:00:00 AM Note that passing CultureInfo.CurrentCulture as the third parameter is identical to passing null. Or, you can pass a specific...

When passing formal arguments to a generic method, relevant generic type arguments can usually be inferred implicitly. If all generic type can be inferred, then specifying them in the syntax is optional. Consider the following generic method. It has one formal parameter and one generic type paramet...

Type constraints are able to force a type parameter to implement a certain interface or class. interface IType; interface IAnotherType; // T must be a subtype of IType interface IGeneric<T> where T : IType { } // T must be a subtype of IType class Generic<T> where T...

It is possible to specify whether or not the type argument should be a reference type or a value type by using the respective constraints class or struct. If these constraints are used, they must be defined before all other constraints (for example a parent type or new()) can be listed. // TRef mus...

By using the new() constraint, it is possible to enforce type parameters to define an empty (default) constructor. class Foo { public Foo () { } } class Bar { public Bar (string s) { ... } } class Factory<T> where T : new() { public T Create() { re...

A method can declare any number of parameters (in this example, i, s and o are the parameters): static void DoSomething(int i, string s, object o) { Console.WriteLine(String.Format("i={0}, s={1}, o={2}", i, s, o)); } Parameters can be used to pass values into a method, so that th...

A method can return either nothing (void), or a value of a specified type: // If you don't want to return a value, use void as return type. static void ReturnsNothing() { Console.WriteLine("Returns nothing"); } // If you want to return a value, you need to specify its type. st...

You can use default parameters if you want to provide the option to leave out parameters: static void SaySomething(string what = "ehh") { Console.WriteLine(what); } static void Main() { // prints "hello" SaySomething("hello"); // prints &quot...

The yield keyword is used to define a function which returns an IEnumerable or IEnumerator (as well as their derived generic variants) whose values are generated lazily as a caller iterates over the returned collection. Read more about the purpose in the remarks section. The following example has a...

public IEnumerable<User> SelectUsers() { // Execute an SQL query on a database. using (IDataReader reader = this.Database.ExecuteReader(CommandType.Text, "SELECT Id, Name FROM Users")) { while (reader.Read()) { int id = reader.GetInt32(0...

using System.Collections.Generic; using System.Collections.ObjectModel; using System.ComponentModel.Composition; namespace Demo { [Export(typeof(IUserProvider))] public sealed class UserProvider : IUserProvider { public ReadOnlyCollection<User> GetAllUsers() ...

using System; using System.ComponentModel.Composition; namespace Demo { public sealed class UserWriter { [Import(typeof(IUserProvider))] private IUserProvider userProvider; public void PrintAllUsers() { foreach (User user in this.user...

class Program { static void Main(string[] args) { // Run 2 Tasks. var task1 = Task.Run(() => PerformAction(1))); var task2 = Task.Run(() => PerformAction(2))); // Wait (i.e. block this thread) until both Tasks are complete. Task.WaitA...

1 - Create an empty folder, it will contain the files created in the next steps. 2 - Create a file named project.json with the following content (adjust the port number and rootDirectory as appropriate): { "dependencies": { "Microsoft.AspNet.Server.Kestrel": "1.0.0...

Developers can be caught out by the fact that type inference doesn't work for constructors: class Tuple<T1,T2> { public Tuple(T1 value1, T2 value2) { } } var x = new Tuple(2, "two"); // This WON'T work... var y = new Tuple<int, string>(2, "t...

Use parentheses around the expression to the left of the => operator to indicate multiple parameters. delegate int ModifyInt(int input1, int input2); ModifyInt multiplyTwoInts = (x,y) => x * y; Similarly, an empty set of parentheses indicates that the function does not accept parameters. ...