Issue using Distinct within a list of objects

Asked Aug 21 '19 at 15:23

Active Aug 21 '19 at 17:49

Viewed 48 times

when I'm trying to remove duplicates from a list of custom objects,

the following are my failed attempt:

model.DatesList = model.DatesList .Distinct().ToList();

2 -

List<DateTimeMask> newDates = new List<DateTimeMask>();
foreach (DateTimeMask _date in DatesList)
{
   if (!newDates.Contains(_date)) newDates.Add(_date);
}
DatesList = newDates;

3 -

model.DatesList = model.DatesList.Select(x=> new DateTimeMask
                                  {
                                    DayOfTheWeek = x.DayOfTheWeek,
                                    DateToString = x.DateToString,
                                    DateTallinn = x.DateTallinn,
                                  }).Distinct().ToList();

What am I doing wrong?

thanks for the help

edit: this is how the object look like

public class DateTimeMask
{
   public string DayOfTheWeek { get; set; }
   public string DateToString { get; set; }
   public DateTime DateTallinn { get; set; }
}

edited Aug 21 '19 at 17:49

KJSR

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asked Aug 21 '19 at 15:23

Francesco Iapicca

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What does `DateTimeMask` look like? Does it implement equality? – Jonathon Chase Aug 21 '19 at 15:29
it's just something to help me to show stuff easily with @diplayfor [updated] – Francesco Iapicca Aug 21 '19 at 15:34
Could you perhaps show a small subset of the data that you expect to work, but doesn't? E.g. Do the dates contain times? – Rob Aug 21 '19 at 15:35
1

Since it's a class, the default check for equality is referential equality, so distinct will only remove objects that are the same reference, not ones with the same values. – Jonathon Chase Aug 21 '19 at 15:39
I think that's it, thanks @JonathonChase – Francesco Iapicca Aug 21 '19 at 15:43

Issue using Distinct within a list of objects

0 Answers0