} //json序列号加上OptOut会排除自身列表，不加会排序其它的属性，故通过这个中转
/// <summary>
/// 列表
/// </summary>
/// <param name="items"></param>
/// <param name="page"></param>
/// <param name="totalCount"></param>
public PageList(IEnumerable <T> items, PageArgument page, int totalCount)
{
if (totalCount != 0)
{
this.AddRange(items);
//this.List.AddRange(items);
}
this.Page = page;
this.TotalCount = totalCount;
this.AllPages = (int)Math.Ceiling(totalCount / (double)page.PageSize);
}
/// <summary>
/// 当请求页码数大于最大页码数时，重置为最大页码数
/// </summary>
/// <param name="page">原分页参数</param>
/// <param name="total">数据总条数</param>
/// <returns>分页参数</returns>
public static PageArgument ToCurrentPage(this PageArgument page, int total)
{
page = page ?? new PageArgument();
// 获取最大页码数（向上取整）
var maxPage = Convert.ToInt32(Math.Ceiling(total / (double)page.PageSize));
// 若当前最大页码数小于前端传入请求页码数时，请求页码数重置为当前最大页码数
if (maxPage < page.PageIndex)
{
page.PageIndex = maxPage;
}
return(page);
}
/// <summary>
/// 获取分页结果
/// </summary>
/// <typeparam name="T">数据item类型</typeparam>
/// <param name="allItems">IQueryable对象</param>
/// <param name="page">分页参数</param>
/// <param name="pageIndexRange">超出最大页显示最后一页，默认false</param>
/// <param name="sortModels">排序规则</param>
/// <returns></returns>
public static PageList <T> ToPageList <T>(this IQueryable <T> allItems, PageArgument page, bool pageIndexRange = false, IEnumerable <SortModel> sortModels = null)
{
page = page ?? new PageArgument();
var itemIndex = (page.PageIndex - 1) * page.PageSize;
var pageOfItems = allItems.OrderBy(sortModels).Skip(itemIndex).Take(page.PageSize);
var totalItemCount = allItems.Count();
if (totalItemCount <= 0)
{
return(new PageList <T>());
}
if (pageIndexRange)
{
page.ToCurrentPage(totalItemCount);
}
return(new PageList <T>(pageOfItems, page, totalItemCount));
}
/// <summary>
/// 根据page对象生成Limit字符串_Mysql版
/// </summary>
/// <param name="page"></param>
/// <returns></returns>
public static string ToMySqlLimitSql(this PageArgument page)
{
page = page ?? new PageArgument();
return($" limit {page.PageSize * (page.PageIndex - 1)},{page.PageSize} ");
}
