In this chapter, we will learn about the most interesting new features of Visual Studio 2017.
We will use Visual Studio Code as a cross-platform editor for C# and some other languages.

We will install the OmniSharp library to have the benefits of intellisense and language support, just as VS does, on other IDEs on macOS and Linux.

We will also discover the new open source and cross-platform compiler named Roslyn, and will understand what its different APIs will bring to us.

Finally, we will discover some useful and relevant new C# 6 features.

There are many new or enhanced features in VS 2017. Let's have a look at a few of them.

1. Feature one—VS project templates:

• 1. We will find a large number of project templates and samples by going to Menu | File | New Project | Installed.
  2. Select a project template related to the technology or language you want to develop with.
  3. We can also download a lot of project templates by going to Menu | File | New Project | Online.
  4. You can search for a template that matches with a technology.

We want to use all the projects which are not necessarily reliable, so it's up to us to verify that. The New Project dialog box appears:

2. Visual Studio Gallery to add extensions...

VS Code is a cross-platform, command-line, and file-folder editor. It can be installed on Windows, Linux, or macOS. We can see VS Code as a cross-platform, lightweight version of VS.

First of all, let's download VS Code from https://code.visualstudio.com/:

1. Let's launch VS Code by double-clicking on Code in the VSCode-linux-x64 folder:

This will open VS Code:

We can press F1 to make the command palette appear, which gives you access to all the functionality of VS Code.

This way, you can also browse...

This recipe explains what OmniSharp is, how to install it, and how it is used on macOS.

In most of the previously mentioned text editors, a package manager is included and will be used to install the OmniSharp package:

1. Edit code on macOS with Atom:

2. Let's install the OmniSharp package on Atom:

3. Next, let's create a new project:

4. Now that OmniSharp is installed, we can use the project scaffolding for .NET projects:

5. After choosing Web Application, the project and the associated files are generated.

6. We can see the Startup.cs class generated:

At the bottom of the picture, we can see the OmniSharp features on Atom, with the little green OmniSharp icon...

In this recipe, we will install and use OmniSharp with the Atom IDE on Linux.

For this recipe, we will use Ubuntu 14.04 VM. We have to make sure that we have followed recipe three to ensure Mono, DNVM, and the Kestrel web server are installed.

1. First, let's add a repository:

sudo add-apt-get repository ppa:webudp8team/atom

2. Next, we update the repository:

sudo apt-get update

3. After that, we install Atom:

sudo apt-get install atom

4. Now we can launch Atom by typing atom in the command line...

We often think about a compiler as a black box which produces an output from an input. Compilers were generally written in C++ because of speed, custom memory, file, and thread management needs. For example, the C# compiler takes .cs files in input and generates .dll files in output.

Now the new Microsoft compiler written in C# and VB, Roslyn, is not just a compiler; it's a .NET compiler platform that we can extend.

Learning to use all Roslyn APIs could be the subject of an entire book. In this recipe, we will just manipulate one of these APIs: the Syntax Trees API. We will create a Syntax Tree and we will analyze it.

In this recipe, we will discover some of the new features in C# 6.

1. Feature one—auto initializer for properties:

Before C# 6, we should initialize a property with a value in the class constructor. There is no point in time before the class constructor, so we should use it. Thanks to C# 6 syntax, we can now initialize a property with a value right on the declaration line. No need to use constructor anymore:

• • Before:

public class Person
{
 Public class Name {get;set;}
 Public Person(){
 Name = "Stephane";
 }
}

• • Now:

Public string Name {get;set;} = "Stephane";

2. Feature two—auto initializer for static properties:

Auto initializers can be applied to...