Question

This is the data I read from database into a datatable.

the datatable called table is now reshaped.

For every same/distinct UnitType + UnitZoom + MemberZoom I create a new Unit and read the MemberId`s into the MemberListId – this should happen in the Order given by the number of the MemberOrder. Sample data:

Unit1: A B C –> P1,P2
Unit2: 1 2 3 –> P9,P12,P4
Unit3: H23 B10 T15 –>X4,T5,Z3,Y1

My code for now that does not proper sort:

 var groupedCollection = table.AsEnumerable()
                                        .GroupBy(row => new
                                        {
                                            UType = row.Field<string>("UnitType"),
                                            UZoom = row.Field<string>("UnitZoom"),
                                            MZoom = row.Field<string>("MemberZoom"),
                                            MOrder = row.Field<int>("MemberOrder"), 
  // I DO NOT WANT the MemberOrder to be in the Group Key, but later on I use this Property to order by it... 
                                        });         


                var unitCollection = groupedCollection
                                    .Select(g => new Unit 
                                    {
                                        UnitType = g.Key.UType,
                                        UnitZoom = g.Key.UZoom,
                                        MemberZoom = g.Key.MZoom,                                   
                                        MemberIdList = g.Select(r => r.Field<string>("MemberId")).OrderBy(b => g.Key.MOrder).ToList(),
                                    });

                List<Unit> units = unitCollection.ToList(); 

Answer 1

Its ordering by static value for list:

MemberIdList = g.Select(r => r.Field<string>("MemberId")).OrderBy(b => g.Key.MOrder).ToList()

U should use something like this: OrderBy(b => b.SomeValue)

it should look like this:

var groupedCollection = table.AsEnumerable()
                                    .GroupBy(row => new
                                    {
                                        UType = row.Field<string>("UnitType"),
                                        UZoom = row.Field<string>("UnitZoom"),
                                        MZoom = row.Field<string>("MemberZoom") 
                                    });         


            var unitCollection = groupedCollection
                                .Select(g => new Unit 
                                {
                                    UnitType = g.Key.UType,
                                    UnitZoom = g.Key.UZoom,
                                    MemberZoom = g.Key.MZoom,                                   
                                    MemberIdList = g.OrderBy(b => b.Field<int>("MemberOrder").Select(r => r.Field<string>("MemberId")).ToList(),
                                });

            List<Unit> units = unitCollection.ToList();