IQueryable查询器扩展Expression动态排序

查询器扩展方法

/// <summary>
        /// 获取分页排序列表
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="queryable">查询器</param>
        /// <param name="PageIndex">当前页</param>
        /// <param name="PageSize">页大小</param>
        /// <param name="condition">查询条件</param>
        /// <param name="orderByExpression">排序表达式</param>
        /// <param name="IsDESC">是否降序</param>
        /// <returns></returns>
        public static async Task<List<T>> GetPageOrderList<T>(this IQueryable<T> queryable,  Expression<Func<T, bool>> condition, PageBase pageBase)
        {
            var property = typeof(T).GetProperty(pageBase.SortField);
            var parameter = Expression.Parameter(typeof(T), "p");
            var propertyAccess = Expression.MakeMemberAccess(parameter, property);
            var orderByExp = Expression.Lambda(propertyAccess, parameter);
            var query = queryable.Where(condition);
            string methodName = pageBase.IsAsc ?"OrderBy" : "OrderByDescending";
            MethodCallExpression resultExp = Expression.Call(typeof(Queryable), methodName, new Type[] { typeof(T), property.PropertyType }, query.Expression, Expression.Quote(orderByExp));
            query = query.Provider.CreateQuery<T>(resultExp);
            pageBase.TotalCount = query.Count();
            var result =await query.Skip((pageBase.PageIndex - 1) * pageBase.PageSize).Take(pageBase.PageSize).ToListAsync();
            return result;
        }

        /// <summary>
        /// 获取排序列表
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="queryable">查询器</param>
        /// <param name="condition">查询条件</param>
        /// <param name="orderByExpression">排序表达式</param>
        /// <param name="IsDESC">是否降序</param>
        /// <returns></returns>
        public static async Task<List<T>> GetOrderList<T>(this IQueryable<T> queryable, Expression<Func<T, bool>> condition, PageBase pageBase)
        {
            var property = typeof(T).GetProperty(pageBase.SortField, BindingFlags.IgnoreCase);
            var parameter = Expression.Parameter(typeof(T), "p");
            var propertyAccess = Expression.MakeMemberAccess(parameter, property);
            var orderByExp = Expression.Lambda(propertyAccess, parameter);
            var query = queryable.Where(condition);
            string methodName = pageBase.IsAsc ? "OrderBy" : "OrderByDescending";
            MethodCallExpression resultExp = Expression.Call(typeof(Queryable), methodName, new Type[] { typeof(T), property.PropertyType }, query.Expression, Expression.Quote(orderByExp));
            query = query.Provider.CreateQuery<T>(resultExp);
            pageBase.TotalCount = query.Count();
            var result = await query.ToListAsync();
            return result;
        }

分页类

public class PageBase
    {
        /// <summary>
        /// 当前页
        /// </summary>
        [Required(ErrorMessage = "页码不可为空.")]
        public int PageIndex { get; set; }

        /// <summary>
        /// 每页条数
        /// </summary>
        [Required(ErrorMessage = "每页大小不可为空.")]
        public int PageSize { get; set; }

        /// <summary>
        /// 排序列
        /// </summary>
        public string SortField { get; set; }

        /// <summary>
        /// 是否升序
        /// </summary>
        public bool IsAsc { get; set; }

        /// <summary>
        /// 总条数
        /// </summary>
        public int TotalCount { get; set; }

        /// <summary>
        /// 总页数
        /// </summary>
        public int TotalPage
        {
            get
            {
                if (TotalCount > 0)
                {
                    return TotalCount % PageSize > 0 ? (TotalCount / PageSize + 1) : TotalCount / PageSize;
                }
                return 0;
            }
        }
    }