Question

所以我写这个查询，它运行正常：

(from schools in context.Schools
                           // some kind of fancy joins
                           select new SomeLocalDTO()
                           {
                               SchoolId = schools.SchoolId,
                               FancySchoolName = schools.SchoolId + "**** -*****  " + schools.SchoolName

                            })
                        .AsQueryable();
/// I have some fancy code here which will aslso take care of take/skip.
// I WANT TO DO ORDER BY HERE, after the skip and take

问题是我想在完成所有花哨的代码/跳过之后订购。但问题是我在select语句中没有学校名称，而是我拥有的是FancySchoolName。我该怎么办？

注1：我无法更改SomeLocalDTO，以便在选择中包含schoolname 注2：根据我的业务要求，我不在乎ABCDEF的结果是否得到ABC或FED。注3：我知道这是一个奇怪的请求，只是一个奇怪的业务需求。

Answer 1

您可以创建一个SomeLocalDTO的子类，其中包括SchoolName，让您的LINQ创建这些对象，然后在返回调用者时向下转发到SomeLocalDTO。

更新：

基于你所说的一切，这就是我仍然在解释你想要的东西......在初始查询之后的OrderBy / Take / Skip，但仍按SchoolName排序：

public class MyDTO: SomeLocalDTO
{
   public string SchoolName {get;set;}
}

var result = (from schools in context.Schools
                           // some kind of fancy joins
                           select new MyDTO()
                           {
                               SchoolId = schools.SchoolId,
                               FancySchoolName = schools.SchoolId + "**** -*****  " + schools.SchoolName,
                               SchoolName = schools.SchoolName    
                            });

return result.OrderBy(s => s.SchoolName)
             .Skip(...)
             .Take(...)
             .Cast<SomeLocalDTO>();

Answer 2

这是一个非常奇怪的订单请求，请采取/跳过，然后是不同的订单，但是：

var something=(from schools in context.Schools
  // some kind of fancy joins
  orderby schools.Name
  select schools);
// take/skip
var result=something.OrderBy(...).Select(schools=>
  new SomeLocalDTO()
  {
    SchoolId = schools.SchoolId,
    FancySchoolName = schools.SchoolId + "**** -*****  " + schools.SchoolName
  });

基于你的困惑，我怀疑这就是你想要的：

var something=context.Schools
  .OrderBy(schools=>schools.SchoolName)
  .Skip(...)
  .Take(...)
  .Select(schools=>
    new SomeLocalDTO()
    {
      SchoolId = schools.SchoolId,
      FancySchoolName = schools.SchoolId + "**** -*****  " + schools.SchoolName
    });

如何在这种特定情况下执行有效的订单？

2 个答案: