/// <summary>
/// 从指定<see cref="IQueryable{T}"/>集合 中查询指定分页条件的子数据集
/// </summary>
/// <typeparam name="TEntity">动态实体类型</typeparam>
/// <typeparam name="TKey">实体主键类型</typeparam>
/// <param name="source">要查询的数据集</param>
/// <param name="predicate">查询条件谓语表达式</param>
/// <param name="pageIndex">分页索引</param>
/// <param name="pageSize">分页大小</param>
/// <param name="total">输出符合条件的总记录数</param>
/// <param name="sortConditions">排序条件集合</param>
/// <returns></returns>
public static IQueryable <TEntity> Where <TEntity, TKey>(this IQueryable <TEntity> source,
Expression <Func <TEntity, bool> > predicate,
int pageIndex,
int pageSize,
out int total,
SortCondition[] sortConditions = null) where TEntity : BaseEntity
{
total = source.Count(predicate);
source = source.Where(predicate);
if (sortConditions == null || sortConditions.Length == 0)
{
source = source.OrderBy(m => m.Id);
}
else
{
int count = 0;
IOrderedQueryable <TEntity> orderSource = null;
foreach (SortCondition sortCondition in sortConditions)
{
orderSource = count == 0
? QueryablePropertySorter <TEntity> .OrderBy(source, sortCondition.SortField, sortCondition.ListSortDirection)
: QueryablePropertySorter <TEntity> .ThenBy(orderSource, sortCondition.SortField, sortCondition.ListSortDirection);
count++;
}
source = orderSource;
}
return(source != null
? source.Skip((pageIndex - 1) *pageSize).Take(pageSize)
: Enumerable.Empty <TEntity>().AsQueryable());
}
/// <summary>
/// 把<see cref="IOrderedQueryable{T}"/>集合继续按指定字段排序方式进行排序
/// </summary>
/// <typeparam name="T">动态类型</typeparam>
/// <param name="source">要排序的数据集</param>
/// <param name="propertyName">排序属性名</param>
/// <param name="sortDirection">排序方向</param>
/// <returns></returns>
public static IOrderedQueryable <T> ThenBy <T>(this IOrderedQueryable <T> source,
string propertyName,
ListSortDirection sortDirection = ListSortDirection.Ascending)
{
source.CheckNotNull("source");
propertyName.CheckNotNullOrEmpty("propertyName");
return(QueryablePropertySorter <T> .ThenBy(source, propertyName, sortDirection));
}
/// <summary>
/// 把<see cref="IQueryable{T}" />集合按指定字段与排序方式进行排序
/// </summary>
/// <param name="source">要排序的数据集</param>
/// <param name="propertyName">排序属性名</param>
/// <param name="sortDirection">排序方向</param>
/// <typeparam name="T">动态类型</typeparam>
/// <returns>排序后的数据集</returns>
public static IOrderedQueryable <T> OrderBy <T>(this IQueryable <T> source,
string propertyName,
ListSortDirection sortDirection = ListSortDirection.Ascending)
{
source.CheckNotNull(nameof(source));
propertyName.CheckNotNullOrEmpty(nameof(propertyName));
return(QueryablePropertySorter <T> .OrderBy(source, propertyName, sortDirection));
}
