How Can I get Distinct values?

Question

Hi,

I don't know  how to get distinct value using lambda linq.

I can't find the option Distinct().

Please help me.

This the code

public async Task<ObservableCollection<ClassJViewModel>> GetAllClassJsS()

        {

   classJs = new ObservableCollection<ClassJViewModel>();

            var db = new SQLite.SQLiteAsyncConnection(App.DBPath);

            var _classJs = await db.Table<ClassJ>().OrderBy(

                p2 => p2.StartJ).ToListAsync();

            foreach (var _classJ in _classJs)

            {

    var classJ = new ClassJViewModel()

                {

                     _id = _classJ._id,

                    SubjectNameJ = _classJ.SubjectNameJ,

                    SubjectColorJ = _classJ.SubjectColorJ,

                    TeacherNameJ = _classJ.TeacherNameJ,

                    TeacherNameShortJ = _classJ.TeacherNameShortJ,

                    RoomNameJ = _classJ.RoomNameJ,

                    YearJ = _classJ.YearJ,

                    MonthJ = _classJ.MonthJ,

                    MonthNameJ = _classJ.MonthNameJ,

                    DayJ = _classJ.DayJ,

                    ymdJ = _classJ.ymdJ,

                    ywdwStartJ = _classJ.ywdwStartJ,

                    ywdwStartSJ = _classJ.ywdwStartSJ,

                    ymJ = _classJ.ymJ,

                    WeekJ = _classJ.WeekJ,

                    DayOfWeekJ = _classJ.DayOfWeekJ,

                    DayOfWeekNameJ = _classJ.DayOfWeekNameJ,

                    ywdwJ = _classJ.ywdwJ,

                    ywJ = _classJ.ywJ,

                    StartJ = _classJ.StartJ,

                    StartMinJ = _classJ.StartMinJ,

                    StartAMPMJ = _classJ.StartAMPMJ,

                    EndJ = _classJ.EndJ,

                    EndMinJ = _classJ.EndMinJ,

                    EndAMPMJ = _classJ.EndAMPMJ,

                    DiffMinJ = _classJ.DiffMinJ,

                    PosXJ = _classJ.PosXJ,

                    PosYJ = _classJ.PosYJ,

                    HeightJ = _classJ.HeightJ,

                   DayOfWeekStartMinJ = _classJ.DayOfWeekStartMinJ,

                    HomeworkDescJ = _classJ.HomeworkDescJ,

                    EventDescJ = _classJ.EventDescJ,

                    NoteDescJ = _classJ.NoteDescJ,

                    HomeworkFixJ = _classJ.HomeworkFixJ,

                    EventFixJ = _classJ.EventFixJ,

                    NoteFixJ = _classJ.NoteFixJ

                };

                classJs.Add(classJ);

                            }

            return classJs;

        }

---

ADRIAN DIBU

Answer 1

Hi Adrian,

by what key do you want to destinct _classJs?

---

lh

Answer 2

Enumerable.Distinct is available: http://msdn.microsoft.com/en-us/library/bb348436(v=vs.110).aspx

Answer 3

Hi,

Thanks for the prompt answer.

The key is SubjectNameJ.

Thanks

Best regards

---

ADRIAN DIBU

Answer 4

Hi,

Thanks Rob for the answer.

I don't know how to use Enumerable.Distinct in my context.

All what I need is to change something in the line

            var db = new SQLite.SQLiteAsyncConnection(App.DBPath);

            var _classJs = await db.Table<ClassJ>().OrderBy(

                p2 => p2.StartJ).ToListAsync();

Now it works OK I get multiple records and I want only one value

Thanks

---

ADRIAN DIBU

Answer 5

Apply the Distinct method before the ToListAsync method:

var _classJs = await db.Table<ClassJ>().OrderBy(p2 => p2.StartJ).Distinct().ToListAsync();

Answer 6

Hi,

Thanks Magnus for the prompt answer.

I tried and I got

'SQLite.AsyncTableQuery<Class_Time.Models.ClassJ>' does not contain a definition for 'Distinct' and no extension method 'Distinct' accepting a first argument of type 'SQLite.AsyncTableQuery<Class_Time.Models.ClassJ>' could be found (are you missing a using directive or an assembly reference?)

Thanks

---

ADRIAN DIBU

Answer 7

Hi,

I made 2 lists and I applied Distinct

private async Task<string> GetDataSunSSS()

 {

      weekJsViewModel1 = new WeekJsViewModel();

      weekJs1 = new ObservableCollection<WeekJViewModel>();

      weekJs1 = await weekJsViewModel1.GetAllWeekJs();

     if (weekJs1.Count() > 0)

     {

         listSubjN = new List<string>();

         listSubjC = new List<string>();

         foreach (var prime995 in subjectJs1) // Loop through List with foreach

         {

             listSubjN.Add(prime995.SubjectNameJ.ToString());

             listSubjC.Add(prime995.SubjectColorJ.ToString());

         }

     }

     listSubjNDistinct =  listSubjN.Distinct().ToList();

     listSubjCDistinct = listSubjC.Distinct().ToList();

     SunClassJsViewSourceSSS.Source = listSubjCDistinct; // weekJs1;

     SunClassJsGridViewSSS.SelectedItem = null;

  return "Sunday";

 }

    The problem is I don't know how to Bind the two lists to the GridView

When it was bind to database I used BindingSubjectNameJand BindingSubjectColorJ and it worked with weeekJs1.

With lists what I suppose to use?????????

    <DataTemplate x:Key="ClassJTemplateSSS">

       <StackPanel  x:Name="panelMonSSS" Orientation="Horizontal" HorizontalAlignment="Left" Height="50" Background="{Binding SubjectColorJ}" Width="50">

 <TextBlock x:Name="txtSubjecNaameJSSS" Text="{Binding SubjectNameJ}" Foreground="Black" Height="19"  TextWrapping="Wrap" VerticalAlignment="Top" FontSize="14" FontWeight="SemiBold"/>

                </StackPanel>

 </DataTemplate>

   <GridView x:Name="SunClassJsGridViewSSS" Background="Black"  Height="50"

                    Margin="0,0,0,0"

                    ScrollViewer.HorizontalScrollBarVisibility="Disabled"

                    Foreground="White"    

                    SelectionMode="Single"

                    IsItemClickEnabled="True"

                    ItemsSource="{Binding Mode=OneWay, Source={StaticResource SunClassJsViewSourceSSS}}"

                    ItemTemplate="{StaticResource ClassJTemplateSSS}"

              >

     <GridView.ItemsPanel>

          <ItemsPanelTemplate>

                      <WrapGrid Orientation="Vertical"/>

          </ItemsPanelTemplate>

       </GridView.ItemsPanel>

        </GridView>

 Thanks

 

---

ADRIAN DIBU

Answer 8

Hi,

Thanks Magnus for the prompt answer.

I tried and I got

'SQLite.AsyncTableQuery<Class_Time.Models.ClassJ>' does not contain a definition for 'Distinct' and no extension method 'Distinct' accepting a first argument of type 'SQLite.AsyncTableQuery<Class_Time.Models.ClassJ>' could be found (are you missing a using directive or an assembly reference?)

Thanks

---

ADRIAN DIBU

You could apply the Distinct method on the returned list then:

var db = new SQLite.SQLiteAsyncConnection(App.DBPath);
List<ClassJ> _classJs = await db.Table<ClassJ>().OrderBy(p2 => p2.StartJ).ToListAsync();
_classJs = _classJs.Distinct().ToList();

Answer 9

 Hi,

I tried

public class SubjColor

    {

        public string Subj { get; set; }

        public string Col { get; set; }

    }

private async Task<string> GetDataSunSS()

 {

      weekJsViewModel1 = new WeekJsViewModel();

      weekJs1 = new ObservableCollection<WeekJViewModel>();

      weekJs1 = await weekJsViewModel1.GetAllWeekJs();

     if (weekJs1.Count() > 0)

     {

         listSubjN = new List<string>();

         listSubjC = new List<string>();

         subjColors = new List<SubjColor>();

 

         foreach (var prime995 in weekJs1) // Loop through List with foreach

         {

             listSubjN.Add(prime995.SubjectNameJ.ToString());

             listSubjC.Add(prime995.SubjectColorJ.ToString());

             subjColors.Add(new SubjColor { Subj = prime995.SubjectNameJ.ToString(), Col = prime995.SubjectColorJ.ToString() });

         }

              listSubjNDistinct = new List<string>();

              listSubjNDistinct =  listSubjN.Distinct().ToList();

              listSubjCDistinct = new List<string>();

              listSubjCDistinct = listSubjC.Distinct().ToList();

              subjColorsDistinct = new List<SubjColor>();

              subjColorsDistinct = subjColors.Distinct().ToList();

             // SunClassJsViewSourceSS.Source = listSubjCDistinct; // works  colors are Distinct

             // SunClassJsViewSourceSS.Source = listSubjNDistinct; // works names are distinct

              // SunClassJsViewSourceSS.Source =  weekJs1; working but not distinct

              SunClassJsViewSourceSS.Source = subjColorsDistinct; // works but not distinct ????????????? Why???

weekJs1.Distinct().ToList();

// SunClassJsViewSourceSS.Source =   // working but not distinct

               SunClassJsGridViewSS.SelectedItem = null;

     }

     return "Sunday";

 }

---

ADRIAN DIBU

Answer 10

Hi,

Thanks for help.

I found the solution:

 public class SubjColor
    {
        public string Subj { get; set; }
        public string Col { get; set; }
         public class Comparer : IEqualityComparer<SubjColor>
    {
        public bool Equals(SubjColor x, SubjColor y)
        {
            return x.Subj == y.Subj
                && x.Col == y.Col;
        }

        public int GetHashCode(SubjColor obj)
        {
            return (obj.Subj + obj.Col).GetHashCode();
        }
    }
}

Usage:

vardistinct = subjColors.Distinct(newSubjColor.Comparer());

Thanks

---

ADRIAN DIBU