Merge two List<object> into one List in Linq

Question

I have two lists. BeamElevations and FloorElevations. How can I merge these into Elevations

Answer 1

 List<Elevation> Elevations= FloorElevations.Concat(BeamElevations).ToList();

Answer 2

Use List.AddRange

   list1.AddRange(list2);
   list1.OrderBy(l => l.Elevation);

Answer 3

Use Concat and OrderBy

var result = list1.Concat(list2).OrderBy(x => x.Elevation).ToList();

If you want to remove duplicates and get an unique set of elements you can also use Union method:

var result = list1.Union(list2).OrderBy(x => x.Elevation).ToList();

In order to make it work properly you need to overide Equals and GetHashCode methods in your class.

Answer 4

Initially you merge them like below:

Elevations=BeamElevations.Union(FloorElevations)
                         .ToList();

Then

Elevations=Elevations.OrderBy(x=>x.Elevation)
                     .ToList();

Or in one step:

Elevations=BeamElevations.Union(FloorElevations)
                         .OrderBy(x=>x.Elevation)
                         .ToList();

Another way to achieve this would be to use Concat

Elevations=BeamElevations.Concat(FloorElevations)
                         .OrderBy(x=>x.Elevation)
                         .ToList();

Answer 5

If there are any devs out there that might be looking for a solution in VB.NET, here you go:

Dim list1 As List(Of MyObject)
Dim list2 As List(Of MyObject)
Dim mergedAndSortedList As List(Of MyObject)

mergedAndSortedList = (From obj In list1.Union(list2)
                       Order By obj.MyPropertyToSortOn
                       Select obj).ToList()