csharpessentials-efcore

name	csharpessentials-efcore
description	Use when wiring EF Core with CSharpEssentials domain models — AuditInterceptor for automatic CreatedAt/UpdatedAt, DomainEventInterceptor for post-save event dispatch, SlowQueryInterceptor for query monitoring, and ToPagedListAsync for offset pagination.

CSharpEssentials.EntityFrameworkCore

EF Core interceptors and pagination utilities that integrate with EntityBase and domain events automatically.

Installation

dotnet add package CSharpEssentials.EntityFrameworkCore

Namespace

using CSharpEssentials.EntityFrameworkCore;

---

Interceptors

Register in DbContext.OnConfiguring:

protected override void OnConfiguring(DbContextOptionsBuilder options)
{
    options
        .AddInterceptors(new AuditInterceptor(auditUserIdProvider))
        .AddInterceptors(new DomainEventInterceptor(eventPublisher))
        .AddInterceptors(new SlowQueryInterceptor(slowQueryHandler, TimeSpan.FromSeconds(5)));
}

Register AuditInterceptor before DomainEventInterceptor in the chain.

AuditInterceptor

Auto-sets CreatedAt, CreatedBy, UpdatedAt, UpdatedBy on EntityBase<TId> entries during SaveChanges.

public class MyAuditProvider : IAuditUserIdProvider
{
    private readonly IHttpContextAccessor _accessor;
    public MyAuditProvider(IHttpContextAccessor accessor) => _accessor = accessor;

    public string GetUserId() =>
        _accessor.HttpContext?.User?.Identity?.Name ?? "system";
}

builder.Services.AddScoped<IAuditUserIdProvider, MyAuditProvider>();

DomainEventInterceptor

Dispatches IDomainEvents raised on entities after SaveChanges completes.

public class MyEventPublisher : IDomainEventPublisher
{
    private readonly IMediator _mediator;
    public MyEventPublisher(IMediator mediator) => _mediator = mediator;

    public Task PublishAsync(IDomainEvent domainEvent, CancellationToken ct) =>
        _mediator.Publish(domainEvent, ct);
}

builder.Services.AddScoped<IDomainEventPublisher, MyEventPublisher>();

SlowQueryInterceptor

Invokes a handler when a query exceeds the configured threshold.

public class MySlowQueryHandler : ISlowQueryHandler
{
    public Task HandleAsync(string sql, TimeSpan elapsed, CancellationToken ct)
    {
        _logger.LogWarning("Slow query ({Elapsed}ms): {Sql}", elapsed.TotalMilliseconds, sql);
        return Task.CompletedTask;
    }
}

---

Pagination

// Offset-based paging
var page = await _db.Orders
    .OrderByDescending(o => o.CreatedAt)
    .ToPagedListAsync(pageNumber: 1, pageSize: 20);

page.Items           // IReadOnlyList<Order>
page.TotalCount      // int — total records (ignoring pagination)
page.PageNumber      // int
page.TotalPages      // int
page.HasNextPage     // bool
page.HasPreviousPage // bool

---

Best Practices

• Register AuditInterceptor before DomainEventInterceptor — audit fields must be set before events fire
• Add a global EF query filter for IsDeleted = false to exclude soft-deleted records automatically
• Use [DomainEventTiming(BeforeSave)] on events that must validate before the transaction commits
• ToPagedListAsync issues two SQL queries (COUNT + data) — add appropriate indexes on sort columns