/// <summary>
/// Convert the <see cref="IQueryable{T}"/> into paginated list.
/// </summary>
/// <typeparam name="T">Type of the <see cref="IQueryable"/>.</typeparam>
/// <param name="source">The type to be extended.</param>
/// <param name="pageIndex">The current page index.</param>
/// <param name="pageSize">Size of the pagiantion.</param>
/// <returns>Returns <see cref="PaginatedList{T}"/>.</returns>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="source"/> is <see langword="null"/>.</exception>
/// <exception cref="ArgumentOutOfRangeException">Thrown if <paramref name="pageIndex"/> is smaller than 1.</exception>
/// <exception cref="ArgumentOutOfRangeException">Thrown if <paramref name="pageSize"/> is smaller than 1.</exception>
public static async Task <PaginatedList <T> > ToPaginatedListAsync <T>(
this IQueryable <T> source,
PaginationSpecification <T> specification)
where T : class
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (specification == null)
{
throw new ArgumentNullException(nameof(specification));
}
IQueryable <T> countSource = source;
// modify the IQueryable using the specification's criteria expression
if (specification.Conditions != null && specification.Conditions.Any())
{
foreach (Expression <Func <T, bool> > conditon in specification.Conditions)
{
countSource = source.Where(conditon);
}
}
long count = await countSource.LongCountAsync();
source = source.GetSpecifiedQuery(specification);
List <T> items = await source.ToListAsync();
PaginatedList <T> paginatedList = new PaginatedList <T>(items, count, specification.PageIndex, specification.PageSize);
return(paginatedList);
}
public async Task <PaginatedList <T> > GetListAsync <T>(
PaginationSpecification <T> specification,
CancellationToken cancellationToken = default)
where T : class
{
if (specification == null)
{
throw new ArgumentNullException(nameof(specification));
}
PaginatedList <T> paginatedList = await _dbContext.Set <T>().ToPaginatedListAsync(specification, cancellationToken);
return(paginatedList);
}
/// <summary>
/// Convert the <see cref="IQueryable{T}"/> into paginated list.
/// </summary>
/// <typeparam name="T">Type of the <see cref="IQueryable"/>.</typeparam>
/// <param name="source">The type to be extended.</param>
/// <param name="specification">An object of <see cref="PaginationSpecification{T}"/>.</param>
/// <param name="cancellationToken"> A <see cref="CancellationToken"/> to observe while waiting for the task to complete.</param>
/// <returns>Returns <see cref="Task"/> of <see cref="PaginatedList{T}"/>.</returns>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="source"/> is <see langword="null"/>.</exception>
/// <exception cref="ArgumentNullException">Thrown if <paramref name="specification"/> is smaller than 1.</exception>
public static async Task <PaginatedList <T> > ToPaginatedListAsync <T>(
this IQueryable <T> source,
PaginationSpecification <T> specification,
CancellationToken cancellationToken = default)
where T : class
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (specification == null)
{
throw new ArgumentNullException(nameof(specification));
}
if (specification.PageIndex < 1)
{
throw new ArgumentOutOfRangeException(nameof(specification.PageIndex), $"The value of {nameof(specification.PageIndex)} must be greater than 0.");
}
if (specification.PageSize < 1)
{
throw new ArgumentOutOfRangeException(nameof(specification.PageSize), $"The value of {nameof(specification.PageSize)} must be greater than 0.");
}
IQueryable <T> countSource = source;
// modify the IQueryable using the specification's expression criteria
if (specification.Conditions != null && specification.Conditions.Any())
{
foreach (Expression <Func <T, bool> > conditon in specification.Conditions)
{
countSource = source.Where(conditon);
}
}
long count = await countSource.LongCountAsync(cancellationToken);
source = source.GetSpecifiedQuery(specification);
List <T> items = await source.ToListAsync(cancellationToken);
PaginatedList <T> paginatedList = new PaginatedList <T>(items, count, specification.PageIndex, specification.PageSize);
return(paginatedList);
}
public async Task <PaginatedList <TProjectedType> > GetListAsync <T, TProjectedType>(
PaginationSpecification <T> specification,
Expression <Func <T, TProjectedType> > selectExpression,
CancellationToken cancellationToken = default)
where T : class
where TProjectedType : class
{
if (specification == null)
{
throw new ArgumentNullException(nameof(specification));
}
if (selectExpression == null)
{
throw new ArgumentNullException(nameof(selectExpression));
}
IQueryable <T> query = _dbContext.Set <T>().GetSpecifiedQuery((SpecificationBase <T>)specification);
PaginatedList <TProjectedType> paginatedList = await query.Select(selectExpression)
.ToPaginatedListAsync(specification.PageIndex, specification.PageSize, cancellationToken);
return(paginatedList);
}
public static IQueryable <T> GetSpecifiedQuery <T>(this IQueryable <T> inputQuery, PaginationSpecification <T> specification)
where T : class
{
if (inputQuery == null)
{
throw new ArgumentNullException(nameof(inputQuery));
}
if (specification == null)
{
throw new ArgumentNullException(nameof(specification));
}
if (specification.PageIndex < 1)
{
throw new ArgumentOutOfRangeException(nameof(specification.PageIndex), "The value of pageIndex must be greater than 0.");
}
if (specification.PageSize < 1)
{
throw new ArgumentOutOfRangeException(nameof(specification.PageSize), "The value of pageSize must be greater than 0.");
}
IQueryable <T> query = GetSpecifiedQuery(inputQuery, (SpecificationBase <T>)specification);
// Apply paging if enabled
int skip = (specification.PageIndex - 1) * specification.PageSize;
query = query.Skip(skip).Take(specification.PageSize);
return(query);
}
