language-csharplisted

# C# / .NET ## .NET 8 project shape - Prefer SDK-style projects with explicit `TargetFramework` (`net8.0`) and shared defaults in `Directory.Build.props`. - Keep nullable reference types enabled for new code: `<Nullable>enable</Nullable>`. - Use `ImplicitUsings` when the repository already does; avoid hand-maintaining noisy common imports. - Keep application, domain, infrastructure, and test projects separate when boundaries are real, not just for ceremony. ```xml <PropertyGroup> <TargetFramework>net8.0</TargetFramework> <Nullable>enable</Nullable> <ImplicitUsings>enable</ImplicitUsings> </PropertyGroup> ``` ## Nullable reference types - Treat warnings as design feedback, not noise. Model absence with `T?`, `required`, or a domain type. - Validate nullable inputs at boundaries; keep internals non-null where possible. - Use `ArgumentNullException.ThrowIfNull(value)` for guard clauses. - Avoid `!` except when bridging a framework or serializer limitation; leave a short reason. ```csharp public sealed class User { public required string Email { get; init; } public string? DisplayName { get; init; } } ``` ## Records and value semantics - Use `record` or `readonly record struct` for immutable value-like data. - Use classes for identity, lifecycle, mutation, or behavior-heavy objects. - Be deliberate with `with`: it is copy-with-change, not validation unless constructors enforce invariants. ```csharp public sealed record Money(decimal Amount, string Currency);