Simply add the constructor you want like this: record Rank(int level, string description); record Manager(string FirstName, Rank Rank) { public Manager() : this(“”, new Rank(0, “Entry”)) { } // public Manager(string FirstName, Rank Rank) is auto generated }
The main difference between e != null and e is not null is the way the the compiler executes the comparison. Microsoft: “The compiler guarantees that no user-overloaded equality operator == is invoked when expression x is null is evaluated.” Bottom Line: If you are writing code that you don’t want to depend on someone’s …
To target the various parts of the expanded class, use the appropriate attribute target. For instance: // Target the property, use `property` record Person(string FirstName, string LastName, [property: JsonIgnore] int Age); // Target the backing field of the property, use `field` record Person(string FirstName, string LastName, [field: JsonIgnore] int Age); // Target the constructor parameter, …
I’m late to the party, but this might still help someone… There’s actually a simple solution (but please read the warning below before using it). Define a base record type like this: public abstract record RecordWithValidation { protected RecordWithValidation() { Validate(); } protected virtual void Validate() { } } And make your actual record inherit …
It looks like there is currently no such type available. You can implement this yourself, but beware of the implications if you need this in a production-ready way. It’s not so simple as it may seem at first sight, as this answer by @ryanholden8 demonstrates! For my use case (and as a simplified example) I …
Per the C#9 record proposal, the following should compile, even if not very useful without actual implementations.. // No explicit IEquatable<R> – this is synthesized! public sealed record SimpleVo { // Not virtual, as SimpleVo (R) is sealed. // Accepts SimpleVo? (R?), and not SimpleVo (R), as argument. public bool Equals(SimpleVo? other) => throw new …
Source Generators must be .NET Standard 2.0 to run in Visual Studio 2019+ or .NET Standard 1.x to run in Visual Studio 2017+.
But what about cloning? var r4 = r with { }; performs a shallow clone on r. The clone method is public according to the specification above. But what is its name? The C# compiler has a fairly common trick where it gives generated members names which are illegal in C#, but legal in IL, …
This is a bug in the current preview and the latest master branch (June 27). A simple record in sharplab.io creates the same error. Just add the missing type somewhere in your project using System.ComponentModel; namespace System.Runtime.CompilerServices { [EditorBrowsable(EditorBrowsableState.Never)] internal class IsExternalInit{} } Records and init will work without problem. Only LinqPad 6 seems to …
This is a small bug in Visual Studio 2019 that hasn’t been fixed yet. To solve this, you need to add a dummy class named IsExternalInit with the namespace System.Runtime.CompilerServices anywhere in your project. That will do it. If writing a library it’s best to make this class internal, as otherwise you can end up …