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Short answer

A record is a reference type built for data. Two records of the same type with the same values compare equal. Use with for a copy that changes selected properties. [S1]

Sketch

public record Person(string First, string Last);
var p2 = p1 with { Last = "Smith" };

Points

• Records compare by value, not by reference identity. [S1]
• with gives nondestructive updates. [S1]
• Positional records and record structs are everyday features of the type. [S2]
• Entity Framework Core still expects reference equality for tracked entities. [S1]

Claims

• id: C1 claim: Records of the same type with the same values are equal. source: S1 evidence: "equal if they are of the same type and store the same values"
• id: C2 claim: with expressions support nondestructive mutation. source: S1 evidence: "use a with expression to achieve nondestructive mutation"
• id: C3 claim: EF Core depends on reference equality. source: S1 evidence: "Entity Framework Core depends on reference equality"
• id: C4 claim: Everyday record features include value equality and with expressions. source: S2 evidence: "value equality, positional syntax, and with expressions"

Sources

• [S1] Records (C# reference). Microsoft Learn. https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/record . License: CC BY 4.0 (dotnet/docs). Accessed 2026-11-05.
• [S2] Create record types in C#. Microsoft Learn. https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/tutorials/records . License: CC BY 4.0 (dotnet/docs). Accessed 2026-11-05.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted).

Source notice: .NET documentation © Microsoft. Licensed under Creative Commons Attribution 4.0 International (https://github.com/dotnet/docs/blob/main/LICENSE).

@misc{iil_note_00qak38e,
  author = {{iinventedlight}},
  title = {{C\# records: value equality, with-expressions, positional syntax}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-04},
  url = {https://iinventedlight.com/library/notes/csharp-records/},
  note = {Permanent ID iil:note:00qak38e. License: CC-BY-4.0.},
}

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