C#6.0

Read-only auto-properties

Read-only auto-properties provide a more concise syntax to create immutable types. You declare the auto-property with only a get accessor. These can be set only in the body of a constructor

public string FirstName { get; }

public string LastName { get;  }

Auto-property initializers

Auto-property initializers let you declare the initial value for an auto-property as part of the property declaration.

public ICollection<double> Grades { get; } = new List<double>();

Expression-bodied function members

Many members that you write are single statements that could be single expressions. Write an expression-bodied member instead. It works for methods and read-only properties.

methods:

public override string ToString() => $"{LastName}, {FirstName}";

properties:

public string FullName => $"{FirstName} {LastName}";

using static

The using static enhancement enables you to import the static methods of a single class. You specify the class you're using.

using static System.String;

using static System.Math;

You must use the fully qualified class name, System.String in a static using statement. You cannot use the string keyword instead.

When imported from a static using statement, extension methods are only in scope when called using the extension method invocation syntax. They aren't in scope when called as a static method.

Null-conditional operators

The null conditional operator makes null checks much easier and fluid.

var first = person?.FirstName;

first = person?.FirstName ?? "Unspecified";

this.SomethingHappened?.Invoke(this, eventArgs);

String interpolation

feature enables you to embed expressions in a string. Simply preface the string with $and use expressions between { and } instead of ordinals.

public string FullName => $"{FirstName} {LastName}";

FormattableString str = $"Average grade is {s.Grades.Average()}";

var gradeStr = str.ToString(new System.Globalization.CultureInfo("de-DE"));

Exception filters

Exception Filters are clauses that determine when a given catch clause should be applied. If the expression used for an exception filter evaluates to true, the catch clause performs its normal processing on an exception. If the expression evaluates to false, then the catch clause is skipped.

 catch (System.Net.Http.HttpRequestException e) when (e.Message.Contains("301"))

        {

            return "Site Moved";

        }

The nameof expression

The nameof expression evaluates to the name of a symbol. It's a great way to get tools working whenever you need the name of a variable, a property, or a member field. One of the most common uses for nameof is to provide the name of a symbol that caused an exception

Await in Catch and Finally blocks

C# 5 had several limitations around where you could place await expressions. With C# 6, you can use await in catch or finally expression