EntityFramework动态组合多排序字段

1、建立一个结构，用于多个排序字段组合，这个结构体有两个字段，一个是需要排序的属性名，一个是是否是升序降序的判断

 public struct OrderModelField
    {
        public string propertyName { get; set; }
        public bool IsDESC { get; set; }
    }

2 组合方法

/// <summary>
        /// 根据条件获取多个实体
        /// </summary>
        /// <param name="condition"></param>
        /// <returns></returns>
        public IList<T> GetAllEntity(Expression<Func<T, bool>> condition, int pageIndex, int pageSize, out long total, params OrderModelField[] orderByExpression)
        {
            //条件过滤
            var query = this.QQYALIEntities.Set<T>().Where(condition);

            //创建表达式变量参数
            var parameter = Expression.Parameter(typeof(T), "o");

            if (orderByExpression != null && orderByExpression.Length > 0)
            {
                for (int i = 0; i < orderByExpression.Length; i++)
                {
                    //根据属性名获取属性
                    var property = typeof(T).GetProperty(orderByExpression[i].propertyName);
                    //创建一个访问属性的表达式
                    var propertyAccess = Expression.MakeMemberAccess(parameter, property);
                    var orderByExp = Expression.Lambda(propertyAccess, parameter);

                    string OrderName = "";
                    if (i > 0)
                    {
                        OrderName = orderByExpression[i].IsDESC ? "ThenByDescending" : "ThenBy";
                    }
                    else
                        OrderName = orderByExpression[i].IsDESC ? "OrderByDescending" : "OrderBy";


                    MethodCallExpression resultExp = Expression.Call(typeof(Queryable), OrderName, new Type[] { typeof(T), property.PropertyType }, query.Expression, Expression.Quote(orderByExp));

                    query = query.Provider.CreateQuery<T>(resultExp);
                }
            }

            total = query.Count();
            return query.Skip((pageIndex - 1) * pageSize).Take(pageSize).ToList();
        }