/// <summary>
/// Finds an entity with the given id. If an entity with the given id
/// is being tracked by the context, then it is returned immediately without making a request to the
/// database. Otherwise, a query is made to the database for an entity with the given id
/// and this entity, if found, is returned. If no entity is found, then
/// null is returned. If <paramref name="tracked"/> is <see langword="true"/>,
/// then the entity is also attached to the context, so that subsequent calls can
/// return the tracked entity without a database roundtrip.
/// </summary>
/// <param name="id">The primary id of the entity.</param>
/// <param name="tracked">
/// Whether to put entity to change tracker after it was loaded from database. Note that <c>false</c>
/// has no effect if the entity was in change tracker already (it will NOT be detached).
/// </param>
/// <returns>The entity found, or null.</returns>
/// <remarks>
/// This method is slightly faster than <see cref="DbSet{TEntity}.Find(object[])"/>
/// because the key is known.
/// </remarks>
public static TEntity FindById <TEntity, TProperty>(this IIncludableQueryable <TEntity, TProperty> query, int id, bool tracked = true)
where TEntity : BaseEntity
{
if (id == 0)
{
return(null);
}
return(query.GetDbContext().FindTracked <TEntity>(id) ?? query.ApplyTracking(tracked).SingleOrDefault(x => x.Id == id));
}
/// <summary>
/// Finds an entity with the given id. If an entity with the given id
/// is being tracked by the context, then it is returned immediately without making a request to the
/// database. Otherwise, a query is made to the database for an entity with the given id
/// and this entity, if found, is returned. If no entity is found, then
/// null is returned. If <paramref name="tracked"/> is <see langword="true"/>,
/// then the entity is also attached to the context, so that subsequent calls can
/// return the tracked entity without a database roundtrip.
/// </summary>
/// <param name="id">The primary id of the entity.</param>
/// <returns>The entity found, or null.</returns>
/// <remarks>
/// This method is slightly faster than <see cref="DbSet{TEntity}.Find(object[])"/>
/// because the key is known.
/// </remarks>
public static TEntity FindById <TEntity, TProperty>(this IIncludableQueryable <TEntity, TProperty> query, int id)
where TEntity : BaseEntity
{
if (id == 0)
{
return(null);
}
return(FindTracked <TEntity>(query.GetDbContext(), id) ?? query.SingleOrDefault(x => x.Id == id));
}
/// <summary>
/// Finds an entity with the given id. If an entity with the given id
/// is being tracked by the context, then it is returned immediately without making a request to the
/// database. Otherwise, a query is made to the database for an entity with the given id
/// and this entity, if found, is returned. If no entity is found, then
/// null is returned. If <paramref name="tracked"/> is <see langword="true"/>,
/// then the entity is also attached to the context, so that subsequent calls can
/// return the tracked entity without a database roundtrip.
/// </summary>
/// <param name="id">The primary id of the entity.</param>
/// <param name="tracked">
/// Whether to put entity to change tracker after it was loaded from database. Note that <c>false</c>
/// has no effect if the entity was in change tracker already (it will NOT be detached).
/// </param>
/// <param name="cancellationToken">A <see cref="CancellationToken" /> to observe while waiting for the task to complete.</param>
/// <returns>The entity found, or null.</returns>
/// <remarks>
/// This method is slightly faster than <see cref="DbSet{TEntity}.FindAsync(object[], CancellationToken)(object[])"/>
/// because the key is known.
/// </remarks>
public static ValueTask <TEntity> FindByIdAsync <TEntity, TProperty>(this IIncludableQueryable <TEntity, TProperty> query, int id, bool tracked = true, CancellationToken cancellationToken = default)
where TEntity : BaseEntity
{
if (id == 0)
{
return(ValueTask.FromResult((TEntity)null));
}
var trackedEntity = query.GetDbContext().FindTracked <TEntity>(id);
return(trackedEntity != null
? new ValueTask <TEntity>(trackedEntity)
: new ValueTask <TEntity>(
query.ApplyTracking(tracked).SingleOrDefaultAsync(x => x.Id == id, cancellationToken)));
}
