Tutorial by Examples: ti

Similarly to the ?. operator, the null-conditional index operator checks for null values when indexing into a collection that may be null. string item = collection?[index]; is syntactic sugar for string item = null; if(collection != null) { item = collection[index]; }

// assigning a signed short to its minimum value short s = -32768; // assigning a signed short to its maximum value short s = 32767; // assigning a signed int to its minimum value int i = -2147483648; // assigning a signed int to its maximum value int i = 2147483647; // assigning a s...

// assigning an unsigned short to its minimum value ushort s = 0; // assigning an unsigned short to its maximum value ushort s = 65535; // assigning an unsigned int to its minimum value uint i = 0; // assigning an unsigned int to its maximum value uint i = 4294967295; // assigning an...

Assemblies are the building block of any Common Language Runtime (CLR) application. Every type you define, together with its methods, properties and their bytecode, is compiled and packaged inside an Assembly. using System.Reflection; Assembly assembly = this.GetType().Assembly; Assembl...

You can enumerate through a Dictionary in one of 3 ways: Using KeyValue pairs Dictionary<int, string> dict = new Dictionary<int, string>(); foreach(KeyValuePair<int, string> kvp in dict) { Console.WriteLine("Key : " + kvp.Key.ToString() + ", Value : " +...

// Translates to `dict.Add(1, "First")` etc. var dict = new Dictionary<int, string>() { { 1, "First" }, { 2, "Second" }, { 3, "Third" } }; // Translates to `dict[1] = "First"` etc. // Works in C# 6.0. var dict = new Dicti...

Dictionary<int, string> dict = new Dictionary<int, string>(); dict.Add(1, "First"); dict.Add(2, "Second"); // To safely add items (check to ensure item does not already exist - would throw) if(!dict.ContainsKey(3)) { dict.Add(3, "Third"); } Al...

public async Task<JobResult> GetDataFromWebAsync() { var nextJob = await _database.GetNextJobAsync(); var response = await _httpClient.GetAsync(nextJob.Uri); var pageContents = await response.Content.ReadAsStringAsync(); return await _database.SaveJobResultAsync(pageContents); } ...

When you want to catch an exception and do something, but you can't continue execution of the current block of code because of the exception, you may want to rethrow the exception to the next exception handler in the call stack. There are good ways and bad ways to do this. private static void AskTh...

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...

public class Model { public string Name { get; set; } public bool? Selected { get; set; } } Here we have a Class with no constructor with two properties: Name and a nullable boolean property Selected. If we wanted to initialize a List<Model>, there are a few different ways to ex...

public delegate int ModifyInt(int input); ModifyInt multiplyByTwo = x => x * 2; The above Lambda expression syntax is equivalent to the following verbose code: public delegate int ModifyInt(int input); ModifyInt multiplyByTwo = delegate(int x){ return x * 2; };

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

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(); } ...

Deprecated usage The ConfigurationSettings class was the original way to retrieve settings for an assembly in .NET 1.0 and 1.1. It has been superseded by the ConfigurationManager class and the WebConfigurationManager class. If you have two keys with the same name in the appSettings section of the ...

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...