C# - Top 10 New Features (Part 1 Of 4)

Article Overview

• Background
• How to compile/test with C# 8.0 in MS Visual Studio OR online
  
• Key features and enhancements to C# 8.0
  
• Switch Expression feature
  
• Pre-requisites
• How to compile/test with C# 8.0 in MS Visual Studio OR online
• MS Visual Studio
• Online tool
  
• Key features and enhancements to C# 8.0
  
• Switch Expressions
• Indices and Ranges
  
• Default Interface Members
• Static Local Functions
• Using Declarations
• Nullable Reference Types
• Readonly Struct Members
• Null-Coalescing Assignment
• Async Streams
  
• Property, Tuple, and Positional Patterns
  
• Switch Expression feature
• Points
  
• Example
• Summary

Background

 

There was a situation where I had to know all the key important features and enhancements in C# 8.0. There are a number of articles and blogs where you can find detailed explanations of new features of C# 8.0.

 

Hence, to understand each one in detail, I went through various sites instead of one single place. So, here I am putting all the key details along with key points as well as examples with code in one place. This way, you can get most of all information from a single place.

 

I have divided this whole article into 4 parts for making it easy to understand with step by step movement to go ahead.

 

This article mainly focuses on three key things.

• How to compile/test with C# 8.0 in MS Visual Studio OR online
  
• Key features and enhancements to C# 8.0
  
• Switch Expressions
  

Here, I have kept all the implementation details along with a complete example.

 

Prerequisites

 

You should have a basic knowledge of C#.

How to compile/test with C# 8.0 in MS Visual Studio OR online

 

First of all, before you start, you have to make the environment ready which can compile your C# 8.0 code.

There are two ways of doing this.

• MS Visual Studio
  
• Online tool 
  

MS Visual Studio

Go to “Advanced Build Settings” and set “Language version” to “C# 8.0 (beta)”.

 

 

Online

There are various online tools where you can write, compile, and execute your code online. I am using “C# Online Compiler | .NET Fiddle”  where you have to set “Compiler” to “.NET Core 3.0”.

  

Key features and enhancements to C# 8.0

 

C# 8.0 added the following key features and enhancements to the C# language.

• Switch Expressions
• Indices and Ranges
  
• Default Interface Members
• Static Local Functions
• Using Declarations
• Nullable Reference Types
• Readonly Struct Members
• Null-Coalescing Assignment
• Async Streams
• Property, Tuple, and Positional Patterns
  

Now, let us discuss each feature one by one in detail.

 

For your reference, I have kept all the examples in a single .cs file and uploaded them with this article.

 

Switch Expression feature

 

Below are the key syntax improvements:

• Bodies are expressions, not statements.
• Case and : elements are replaced with =>. It is more concise and intuitive.
• Variable comes before the switch keyword. It is visually easy to distinguish the switch expression from the switch statement.
• Default case is replaced with a _ discard.

Now, let us understand by examples.

Example-1

var (a, b, option) = (10, 5, "+");

var example1 = option switch
{
        "+" => a + b,
        "-" => a - b,
        _ => a * b
};

Console.WriteLine(example1);

Example-2

var value = 25;

int example2 = value switch
{
        _ when value > 10 => 0,
        _ when value <= 10 => 1
};

Console.WriteLine( example2);

Example-3

Calculation c1 = new Calculation(50, 10, "*");
c1.print();

Calculation c2 = new Calculation(50, 10, "+");
c2.print();


public class Calculation
{
    public Calculation(int a, int b, string operation)
    {
        this.FirstNumber = a;
        this.SecondNumber = b;
        this.Operation = operation;

        this.ResultNumber = this.Operation switch
        {
                "+" => this.FirstNumber + this.SecondNumber,
                "-" => this.FirstNumber - this.SecondNumber,
                "/" => this.FirstNumber / this.SecondNumber,
                "*" => this.FirstNumber * this.SecondNumber,
                _ => -1
        };
    }

    public int FirstNumber { get; set; }

    public int SecondNumber { get; set; }

    public string Operation { get; set; }

    public int ResultNumber { get; set; }

    public void print()
    {
        Console.WriteLine($"{this.FirstNumber} {this.Operation} {this.SecondNumber} = {this.ResultNumber}");
    }
}

Summary

 

Now, I believe you will be able to compile/test with C# 8.0 in MS Visual Studio OR online, you know the key new features and enhancements to C# 8.0, and you understand the Switch Expression feature.

 

In my next article, I will cover the next three features such as "Indices and Ranges", "Default Interface Members", and "Static Local Functions".