Linq 与不同的连接和排序依据

Question

我有一个查询似乎根本不遵守我的 order by 子句，

有人可以帮我解决这个问题吗？

   Dim Result = ((From z As lnkCategorySubCategory In dbContext.lnkCategorySubCategories
                   Join x As SubItem In dbContext.SubItems On x.Id Equals z.CategoryId
                   Join p As lnkItemsCategory In dbContext.lnkItemsCategories On z.CategoryId Equals p.ItemCategoryId
                   Order By z.IsHeadColumn Descending
                   Order By z.Order Descending
                   Select x.Name)).Distinct

Answer 1

如果没有更多信息，我无法告诉您是什么导致了您的问题。但是，如果我要大胆猜测，我建议您更改此设置：

Order By z.IsHeadColumn Descending
Order By z.Order Descending

为此：

Order By z.IsHeadColumn, z.Order descending

Answer 2

我觉得 orderby z.IsHeadColumn descending, z.Order descending 应该可以

Answer 3

这里的问题是我不是select我选择排序的列，所以我需要写一些更像这样的东西来解决这个问题

  Dim Result = ((From z As lnkCategorySubCategory In dbContext.lnkCategorySubCategories
                       Join x As SubItem In dbContext.SubItems On x.Id Equals z.CategoryId
                       Join h As lnkSubItemImageLink In dbContext.lnkSubItemImageLinks On x.Id Equals h.SubItemId
                       Join p As lnkItemsCategory In dbContext.lnkItemsCategories On z.CategoryId Equals p.ItemCategoryId
                       Select x.Name, h.ImageLink, z.IsHeadColumn, z.Order)).Distinct.OrderByDescending(
                       Function(u) u.IsHeadColumn).ThenBy(Function(j) j.Order).ToDictionary(Function(x) x.Name, Function(h) h.ImageLink)

Linq 与不同的连接和排序依据

Linq with join distinct and order by

linq

vb.net

join

sql-order-by