DKNet

Generate and validate event payloads

Part of DKNet.EfCore.DtoGenerator. Install DKNet.EfCore.Abstractions alongside the generator. Replace Program.cs with this convention-form example:

using DKNet.EfCore.Abstractions.Events;

var payload = new ProductTouchedCreatedEvent { Id = 1, Name = "Coffee" };
Console.WriteLine(payload.Name); // Coffee

[RaisesEvent("Touched", EventOperations.Created, Exclude = new[] { nameof(Product.InternalCost) })]
public sealed class Product
{
    public int Id { get; set; }
    public string Name { get; set; } = "";
    public decimal InternalCost { get; set; }
}

RaisesEventValidator checks event operations, names and payload filters, then either validates a named GenerateDto payload or composes and emits a convention record.

Form	Declaration	Payload shape owner
Explicit type	`[RaisesEvent(typeof(ProductCreatedEvent), EventOperations.Created)]`	Your `[GenerateDto(typeof(Product))]` partial payload.
Labelled convention	`[RaisesEvent("Touched", EventOperations.Created)]`	Generated `ProductTouchedCreatedEvent`.
Label-less convention	`[RaisesEvent(EventOperations.Created)]`	Generated `ProductCreatedEvent`.

Convention names combine entity name, optional label, sorted narrowing properties, operations in Created/Updated/Deleted order, then Event. EventNameComposer is compile-linked from Abstractions and shared with the runtime. Convention payloads accept Include/Exclude and project exclusions but omit navigation properties: navigation classes and collections shaped as an array, List<T>, IList<T>, ICollection<T> or IEnumerable<T>. Read-only and set collections (IReadOnlyCollection<T>, IReadOnlyList<T>, HashSet<T>) are not recognised and stay in the payload. A compatible handwritten partial record without [GenerateDto] can extend the emitted record.

⚙️ Configuration reference

Diagnostic	Severity	Meaning
`DKDTOGEN001`	Warning	A target threw during generation; that target is skipped.
`DKDTOGEN002`	Warning	The entity has no eligible properties.
`DKDTOGEN003`	Info	Property filtering summary.
`DKDTOGEN004`	Warning	Non-empty Include and Exclude conflict; no DTO emitted.
`DKDTOGEN005`	Info	Include bypasses global exclusions.
`DKRAISEVT001`	Error	A narrowing property is invalid or nested.
`DKRAISEVT002`	Error	Named payload lacks GenerateDto or targets a different entity.
`DKRAISEVT003`	Warning	Narrowing supplied without Updated; ignored at runtime.
`DKRAISEVT004`	Error	Composed name collides with an incompatible type.
`DKRAISEVT005`	Error	Label is not a constant or composed identifier is invalid.
`DKRAISEVT006`	Error	Different entities in one namespace compose the same name.
`DKRAISEVT007`	Error	No operation is declared.
`DKRAISEVT008`	Error	Multiple rules on one entity compose the same name.
`DKRAISEVT009`	Error	Convention Include and Exclude conflict.
`DKRAISEVT010`	Error	Convention payload filter property is invalid or nested.
`DKRAISEVT011`	Error	Payload filters supplied on the explicit type form.

All use category DKNet.EfCore.DtoGenerator. Standard MSBuild EmitCompilerGeneratedFiles and CompilerGeneratedFilesOutputPath can write generated source for inspection; use an intermediate directory such as obj/Generated.

🧱 Where it fits

The compiler architecture separates generation from runtime event dispatch. The latter needs its own hook, mapper and publisher registration.

⚠️ Gotchas & limits

Filters on the explicit type form are rejected: put them on that payload’s [GenerateDto] instead.
A type can compile with warnings while no DTO was emitted; downstream member access can then fail. Read diagnostic severity as well as the build result.
Narrowing lists only affect Updated event rules. Generated payloads do not dispatch themselves.

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