不允许在 IEnumerable> 中重复

本文关键字：string Guid IEnumerable KeyValuePair 不允许 | 更新日期: 2023-09-27 18:35:18

我正在使用linq获取数据并将数据插入IEnumerable>中。但有时我得到重复的键值对，我不想这样，因为我正在做一个 ToDictionary（pair => 对。键，对 =>对。值）在 IEnumerable 上。

这是我的代码：

public Dictionary<Guid, string> GetCitizensWithUnwarrentedAbsence(Guid counselorId, DateTime date)
{
    var now = DateTime.Now;
    var startInterval = Convert.ToDateTime(date.Date.ToShortDateString());
    var endInterval = Convert.ToDateTime(date.Date.ToShortDateString()).AddHours(23).AddMinutes(59);
    var list = (from c in _context.CitizenCounselorSet
                join p in _context.ActivityLessonParticipantSet on c.Citizen.Id equals p.UserId
                where c.CounselorId == counselorId
                      && c.StartDate < now
                      && (c.EndDate == null || (c.EndDate.HasValue && c.EndDate.Value > now))
                      && p.WasUnwarrantedAbsent
                      && !p.ActivityLesson.IsDeleted
                      && !p.ActivityLesson.IsCancelled
                      && p.ActivityLesson.From >= startInterval
                      && p.ActivityLesson.From <= endInterval
                select new
                {
                    UserId = p.UserId,
                    UserName = p.User.FullName,
                    CPR = p.User.UserName
                }).ToList().Select(a => new KeyValuePair<Guid, string>(a.UserId, a.UserName + " (" + EncryptionUtility.DecryptString(a.CPR).Insert(6, "-") + ")"));
    return list.ToDictionary(pair => pair.Key, pair => pair.Value);
}

我如何确保在获取数据后不会获得重复项或删除重复项？

不允许在 IEnumerable<KeyValuePair<Guid，string>> 中重复

我会在查询结束时进行一些更改。让我们节省空间，并在执行主查询逻辑时从}).ToList()开始，并重新定义其余部分以获取字典：

var yourExistingQueryLogic = ...
                             }).ToList();
var yourUserDictionary = yourExistingQueryLogic
                         .Select(x=>new {x.UserId, UserName = x.UserName+ " (" + EncryptionUtility.DecryptString(a.CPR).Insert(6, "-") + ")"}) //you can simply build an anonymous object here
                         .Distinct() //this will eliminate duplicates
                         .ToDictionary(x=>x.UserId, x=>x.UserName); // DONE!
相关文章：