public static IFetchSpecification <T> ThenByDescending <T>(
this IFetchSpecification <T> specification,
Expression <Func <T, object> > keySelector)
{
return(specification
.ThenBy(OrderingDirection.Descending, keySelector));
}
public static IFetchSpecification <T> TakePage <T>(
this IFetchSpecification <T> specification,
int pageNumber,
int pageSize)
{
return(specification
.TakePage(new PaginationExpression(pageSize, pageNumber)));
}
public IEnumerable <TEntity> Find(
ISpecification <TEntity>?specification = null,
IFetchSpecification <TEntity>?fetchSpecification = null)
{
return(_dbSet
.Evaluate(specification)
.EvaluateFetch(fetchSpecification));
}
public static IFetchSpecification <T> ThenInclude <T, TPreviousProperty, TProperty>(
this IFetchSpecification <T> specification,
Expression <Func <TPreviousProperty, TProperty> > keySelector)
{
var lastInclude = specification.Include.Last();
((IncludeExpression <T>)lastInclude).ThenInclude(keySelector);
return(specification);
}
public static IFetchSpecification <T> WithNoOrder <T>(
this IFetchSpecification <T> specification)
{
return(new FetchSpecification <T>
(
include: specification.Include,
orderBy: null,
takePage: specification.TakePage
));
}
private static IFetchSpecification <T> TakePage <T>(
this IFetchSpecification <T> specification,
PaginationExpression?takePage)
{
return(new FetchSpecification <T>
(
include: specification.Include,
orderBy: specification.OrderBy,
takePage: takePage
));
}
private static IFetchSpecification <T> OrderBy <T>(
this IFetchSpecification <T> specification,
OrderingDirection direction,
Expression <Func <T, object> > keySelector)
{
return(new FetchSpecification <T>
(
include: specification.Include,
orderBy: new[] { new OrderingExpression <T>(direction, keySelector), },
takePage: specification.TakePage
));
}
private static IFetchSpecification <T> ThenBy <T>(
this IFetchSpecification <T> specification,
OrderingDirection direction,
Expression <Func <T, object> > keySelector)
{
var orderBy = specification.OrderBy.ToList();
orderBy.Add(new OrderingExpression <T>(direction, keySelector));
return(new FetchSpecification <T>
(
include: specification.Include,
orderBy: orderBy,
takePage: specification.TakePage
));
}
internal static IQueryable <TEntity> EvaluateFetch <TEntity>(
this IQueryable <TEntity> query,
IFetchSpecification <TEntity>?specification)
where TEntity : class
{
if (specification == null)
{
return(query);
}
foreach (var includeExpression in specification.Include)
{
query = (IQueryable <TEntity>)includeExpression.AddIncludes(query);
}
for (var i = 0; i < specification.OrderBy.Count; i++)
{
var(direction, keySelector) = specification.OrderBy[i];
switch (direction)
{
case OrderingDirection.Ascending:
query = i == 0
? query.OrderBy(keySelector)
: ((IOrderedQueryable <TEntity>)query).ThenBy(keySelector);
break;
case OrderingDirection.Descending:
query = i == 0
? query.OrderByDescending(keySelector)
: ((IOrderedQueryable <TEntity>)query).ThenByDescending(keySelector);
break;
}
}
if (specification.TakePage != null)
{
var(pageSize, pageIndex) = specification.TakePage;
query = query
.Skip(pageSize * pageIndex)
.Take(pageSize);
}
return(query);
}
public static IFetchSpecification <T> Include <T, TProperty>(
this IFetchSpecification <T> specification,
Expression <Func <T, TProperty> > keySelector)
{
var includes = new List <IIncludeExpression <T> >();
if (specification.Include.Any())
{
includes.AddRange(specification.Include);
}
var includeExpr = new IncludeExpression <T>();
includeExpr.Include <T, TProperty>(keySelector);
includes.Add(includeExpr);
return(new FetchSpecification <T>
(
include: includes,
orderBy: specification.OrderBy,
takePage: specification.TakePage
));
}
public static IFetchSpecification <T> TakeAll <T>(
this IFetchSpecification <T> specification)
{
return(specification
.TakePage(null));
}
public IEnumerable <TEntity> Find(
ISpecification <TEntity>?specification = null,
IFetchSpecification <TEntity>?fetchSpecification = null)
{
throw new NotImplementedException();
}
