C# - Remove rows with the same column value from a DataTable

Question

I have a DataTable which looks like this:

 ID   Name    DateBirth
.......................
 1     aa      1.1.11
 2     bb      2.3.11
 2     cc          


        

Answer 1

Not necessarily the most efficient approach, but maybe the most readable:

table = table.AsEnumerable()
    .GroupBy(row => row.Field("ID"))
    .Select(rowGroup => rowGroup.First())
    .CopyToDataTable();

Linq is also more powerful. For example, if you want to change the logic and not select the first (arbitrary) row of each id-group but the last according to DateBirth:

table = table.AsEnumerable()
    .GroupBy(row => row.Field("ID"))
    .Select(rowGroup => rowGroup
                          .OrderByDescending(r => r.Field("DateBirth"))
                          .First())
    .CopyToDataTable();