OrderByDescending 在我的 LINQ 查询中不起作用

Question

I have come across a problem with a query where I'm trying to sort the result by descending but it doesn't do it. I have gone through few posts on stackoverflow with similar issue but none of the solutions seemed to work. I was wondering if someone could point out what is wrong with my code. Heres part of the query relevant to a problem:

from followup in ctx.FollowUps
    .Where(f => f.DestEntityId == user.Id 
           && f.DestEntityType == (int)ContactEntityTypeEnum.User)
    .OrderByDescending(x => x.AddDate)
select new
{ 
    user = new { Firstname = user.Firstname },
    followup = new { followup.NextFollowUpDate }
});

I also tried adding .ToList() before .OrderByDescending() but that didn't solve the problem either.

Answer 1

Following up the comments from @SILENT & @D.Shih your Linq expression is looking a bit odd.

var followUps =  ctx.FollowUps
    .Where(f => f.DestEntityId == user.Id 
           && f.DestEntityType == (int)ContactEntityTypeEnum.User)
    .OrderByDescending(x => x.AddDate)
    .Select(x => new
    { 
        UserFirstname = user.Firstname,
        AddDate = x.AddDate,
        FollowupDate = x.NextFollowUpDate
    }).ToList();

This will order the results by AddDate, not NextFollowUpDate, so I've added AddDate to the output just to avoid confusion between the two, since I don't know how you'd have assessed that they weren't in order based on only seeing the NextFollowUpDate. I don't recommend mixing the LinQL (from/where/select) with the Fluent methods. (above)

There doesn't look to be a point in returning each individual property in a separate anonymous type, just flatten it into a single package since anonymous types are intended for short lives and immediate consumption.