The Catch Block #67- C# 10 Features, .NET 6 Preview 6, and VS 2022 Preview 2

Welcome to the 67th edition of The Catch Block!

In this edition: let's check out a bunch of official and semi-official features coming in C# 10!

Plus: a new Visual Studio 2022 preview; a new .NET 6 preview; musings on GitHub Copilot; and improving our Blazor UI responsiveness.

Check Out Upcoming Features of C# 10!

C# 10 is coming out soon, and included with it are a few changes that I thought my dear readers should know about. A few of these are officially included (that is, included on the Microsoft docs for C# 10), and some of them are not official yet but are pretty much guaranteed to make the cut; we'll call them "semi-official".

Here's five of the coolest upcoming changes:

Official - Const Interpolated Strings

The coolest "official" change is the ability to make const string objects using interpolation (the $ operator) if all the interpolated strings are const themselves.

public const string Name = "John Smith";
public const string Title = "Dr.";

public const string Greeting = $"Hello {Title} {Name}!";

Semi-Official - Null Parameter Checking

C# 10 will probably include the ability to check if a parameter to a method is null, using the !! operator:

public void MyMethod(string param1, SomeClass myClass!!)
{
    //...
}

Any time this method is called, if the value of myClass is null, C# will automatically through an instance of ArgumentNullException.

Semi-Official - field Keyword

In C# right now, we often need to declare properties in a class with a backing private field. Let's pretend we have a User class with a Name field, and there's a restriction on the Name so that it cannot be blank or only whitespace:

public class User
{
    private string _name;
    
    public string Name
    {
        get
        {
            return _name;
        }
        set
        {
            if(string.IsNullOrWhiteSpace(value))
                throw new ArgumentException("Name cannot be blank.");
            _name = value;
        }
    }
}

C# 10 introduces the new field keyword, which allows us to simplify this code to the following:

public class User
{
    private string _name;
    
    public string Name
    {
        get;
        set
        {
            if(string.IsNullOrWhiteSpace(value))
                throw new ArgumentException("Name cannot be blank.");
            field = value;
        }
    }
}

We don't need the get accessor code anymore, because the C# compiler automatically includes it when we use the field keyword.