LINQ多个订单由

问题描述

我创建了一个函数具有follwing参数：

I have created a function that has the follwing parameter:

List<Expression<Func<CatalogProduct, bool>>> orderBy = null

此参数是可选的，如果它充满应该为我创造一个ORDER BY和比构建适应和支持，让我可以订购SQL服务器上的结果。

This parameter is optional, If it is filled it should create a order by and than by constuction for me, so that I can order the result on the SQL server.

我想：

            IOrderedQueryable temp = null;
            foreach (Expression<Func<CatalogProduct, bool>> func in orderBy)
            {
                if (temp == null)
                {
                    temp = catalogProducts.OrderBy(func);
                }
                else
                {
                    temp = temp.ThanBy(func);
                }
            }

但不是没有reconized。是否有人知道我怎么能解决这个问题？

But the than By is not reconized. Does someone know how I can solve this problem?

我把它改为.ThenBy（），但是这只是.OrderBy（后直接允许的），而不是在一个IOrderedQueryable

I changed it to .ThenBy() but this is only allowed directly after the .OrderBy() and not on a IOrderedQueryable

所以临时= catalogProducts.OrderBy（FUNC）.ThenBy（FUNC）;是允许的，但临时= catalogProducts.OrderBy（FUNC）;临时= temp.ThenBy（FUNC）; issn't

so temp = catalogProducts.OrderBy(func).ThenBy(func); is allowed but temp = catalogProducts.OrderBy(func); temp = temp.ThenBy(func); issn't

任何其他建议？

推荐答案

两个问题;首先， ThanBy 应 ThenBy ;其次， ThenBy 仅在通用的类型， IOrderedQueryable＆LT; T＆GT;

Two problems; firstly, ThanBy should be ThenBy; secondly, ThenBy is only available on the generic type, IOrderedQueryable<T>.

于是更改为：

        IOrderedQueryable<CatalogProduct> temp = null;
        foreach (Expression<Func<CatalogProduct, bool>> func in orderBy) {
            if (temp == null) {
                temp = catalogProducts.OrderBy(func);
            } else {
                temp = temp.ThenBy(func);
            }
        }

和你应该进行排序。

这篇关于LINQ多个订单由的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！