Tutorial by Examples: er

using System; using System.IO; using System.Linq; using System.Net.Http; using System.Threading.Tasks; class HttpGet { private static async Task DownloadAsync(string fromUrl, string toFile) { using (var fileStream = File.OpenWrite(toFile)) { using (va...

List<int> l2 = l1.FindAll(x => x > 6); Here x => x > 6 is a lambda expression acting as a predicate that makes sure that only elements above 6 are returned.

public class Person { //Id property can be read by other classes, but only set by the Person class public int Id {get; private set;} //Name property can be retrieved or assigned public string Name {get; set;} private DateTime dob; //Date of Birth property is st...

class Program { public static void Main(string[] args) { Person aPerson = new Person("Ann Xena Sample", new DateTime(1984, 10, 22)); //example of accessing properties (Id, Name & DOB) Console.WriteLine("Id is: \t{0}\nName is:\t'{1}'.\nDOB is...

var now = DateTime.UtcNow; //accesses member of a class. In this case the UtcNow property.

var zipcode = myEmployee?.Address?.ZipCode; //returns null if the left operand is null. //the above is the equivalent of: var zipcode = (string)null; if (myEmployee != null && myEmployee.Address != null) zipcode = myEmployee.Address.ZipCode;

var age = GetAge(dateOfBirth); //the above calls the function GetAge passing parameter dateOfBirth.

var letters = "letters".ToCharArray(); char letter = letters[1]; Console.WriteLine("Second Letter is {0}",letter); //in the above example we take the second character from the array //by calling letters[1] //NB: Array Indexing starts at 0; i.e. the first letter would be give...

var letters = null; char? letter = letters?[1]; Console.WriteLine("Second Letter is {0}",letter); //in the above example rather than throwing an error because letters is null //letter is assigned the value null

using System.Text; //allows you to access classes within this namespace such as StringBuilder //without prefixing them with the namespace. i.e: //... var sb = new StringBuilder(); //instead of var sb = new System.Text.StringBuilder();

6.0 Allows you to import a specific type and use the type's static members without qualifying them with the type name. This shows an example using static methods: using static System.Console; // ... string GetName() { WriteLine("Enter your name."); return ReadLine(); } ...

Notes: This example must be run in administrative mode. Only one simultaneous client is supported. For simplicity, filenames are assumed to be all ASCII (for the filename part in the Content-Disposition header) and file access errors are not handled. using System; using System.IO; using Syst...

The ConfigurationManager class supports the AppSettings property, which allows you to continue reading settings from the appSettings section of a configuration file the same way as .NET 1.x supported. app.config <?xml version="1.0" encoding="utf-8"?> <configuration&gt...

Visual Studio helps manage user and application settings. Using this approach has these benefits over using the appSettings section of the configuration file. Settings can be made strongly typed. Any type which can be serialized can be used for a settings value. Application settings can be...

var collection = new BlockingCollection<int>(5); var random = new Random(); var producerTask = Task.Run(() => { for(int item=1; item<=10; item++) { collection.Add(item); Console.WriteLine("Produced: " + item); Thread.Sleep(random.Next(1...

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...

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...

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...

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...