Tutorial by Examples: i

A task can be created by directly instantiating the Task class... var task = new Task(() => { Console.WriteLine("Task code starting..."); Thread.Sleep(2000); Console.WriteLine("...task code ending!"); }); Console.WriteLine("Starting task..."); t...

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 allTasks = Enumerable.Range(1, 5).Select(n => new Task<int>(() => n)).ToArray(); var pendingTasks = allTasks.ToArray(); foreach(var task in allTasks) task.Start(); while(pendingTasks.Length > 0) { var finishedTask = pendingTasks[Task.WaitAny(pendingTasks)]; Conso...

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 cancellationTokenSource = new CancellationTokenSource(); var cancellationToken = cancellationTokenSource.Token; var task = new Task((state) => { int i = 1; var myCancellationToken = (CancellationToken)state; while(true) { Console.Write...

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...

Structs inherit from System.ValueType, are value types, and live on the stack. When value types are passed as a parameter, they are passed by value. Struct MyStruct { public int x; public int y; } Passed by value means that the value of the parameter is copied for the method, and any...

Classes inherit from System.Object, are reference types, and live on the heap. When reference types are passed as a parameter, they are passed by reference. public Class MyClass { public int a; public int b; } Passed by reference means that a reference to the parameter is passed to t...

An enum is a special type of class. The enum keyword tells the compiler that this class inherits from the abstract System.Enum class. Enums are used for distinct lists of items. public enum MyEnum { Monday = 1, Tuesday, Wednesday, //... } You can think of an enum as a conve...

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...

Every method has a unique signature consisting of a accessor (public, private, ...) ,optional modifier (abstract), a name and if needed method parameters. Note, that the return type is not part of the signature. A method prototype looks like the following: AccessModifier OptionalModifier ReturnTyp...

Calling a static method: // Single argument System.Console.WriteLine("Hello World"); // Multiple arguments string name = "User"; System.Console.WriteLine("Hello, {0}!", name); Calling a static method and storing its return value: string input = System.Con...

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...

You can extend the functionality of existing yield methods by passing in one or more values or elements that could define a terminating condition within the function by calling a yield break to stop the inner loop from executing. public static IEnumerable<int> CountUntilAny(int start, HashSet...

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() ...