LowCodeHub.QueryableExtensions 0.0.1

LowCodeHub.QueryableExtensions

LowCodeHub.QueryableExtensions provides reusable query and EF Core building blocks for ASP.NET Core applications.

Features

• LINQ query extensions for filtering and ordering
• Pagination models and helpers
• Specification pattern helpers
• Lookup entities and query helpers
• Enum-to-lookup code mapping via LookupCodeAttribute
• Localization-related value objects and converters
• EF Core transaction manager with:
  • ExecuteInTransactionAsync
  • ExecuteInTransactionWithRetryAsync
  • optional IsolationLevel overloads

Installation

dotnet add package LowCodeHub.QueryableExtensions

Quick usage

EF Core lookup support

In your DbContext model configuration:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.AddLookupSupport();
    base.OnModelCreating(modelBuilder);
}

In DI registration:

services.AddDbContext<MyDbContext>(options => ...);
services.AddLookupSupport<MyDbContext>();

Transaction manager

services.AddTransactionManager<MyDbContext>();

await transactionManager.ExecuteInTransactionAsync(async scope =>
{
    // data changes
    // auto-commit on success / auto-rollback on failure
});

With retry + isolation level:

await transactionManager.ExecuteInTransactionWithRetryAsync(
    async scope =>
    {
        // data changes
    },
    System.Data.IsolationLevel.ReadCommitted,
    cancellationToken);

Manual commit/rollback is still supported inside scope if needed.

Specifications

var query = dbContext.Users.AsQueryable()
    .WithSpecification(new ActiveUsersSpecification());

Lookups

var options = await lookupRepository.GetOptionsAsync("ORDER_STATUS", "en", cancellationToken: cancellationToken);

Queryable usage is still available:

var options = (await dbContext.Set<LookupItemEntity>()
    .WhereActive()
    .WhereSetCode("ORDER_STATUS")
    .OrderBySortOrder()
    .ToListAsync(cancellationToken))
    .ToLookupOptions("en");

Enum mapping:

public enum OrderStatus
{
    [LookupCode("PENDING")]
    Pending,
    [LookupCode("APPROVED")]
    Approved
}

var code = OrderStatus.Pending.ToCode();
var status = "APPROVED".ToEnum<OrderStatus>();

Best practices

1. Keep specifications focused and composable.
2. Use retry transaction API for transient-failure environments.
3. Normalize lookup codes in persistence and treat them as stable identifiers.
4. Pass explicit IsolationLevel only when business consistency requires it.
5. Keep transaction scopes short and side-effect free.