query - select specific columns from datatable in c# using linq




How do I get a distinct, ordered list of names from a DataTable using LINQ? (5)

To abstract: all of the answers have something in common.

OrderBy needs to be the final operation.

I have a DataTable with a Name column. I want to generate a collection of the unique names ordered alphabetically. The following query ignores the order by clause.

var names =
    (from DataRow dr in dataTable.Rows
    orderby (string)dr["Name"]
    select (string)dr["Name"]).Distinct();

Why does the orderby not get enforced?


To make it more readable and maintainable, you can also split it up into multiple LINQ statements.

  1. First, select your data into a new list, let's call it x1 , do a projection if desired
  2. Next, create a distinct list, from x1 into x2 , using whatever distinction you require
  3. Finally, create an ordered list, from x2 into x3 , sorting by whatever you desire

Try the following

var names = (from dr in dataTable.Rows
             select (string)dr["Name"]).Distinct().OrderBy(name => name);

this should work for what you need.


You can use something like that:

dataTable.Rows.Cast<DataRow>().GroupBy(g => g["Name"]).Select(s => s.First()).OrderBy(o => o["Name"]);

var sortedTable = (from results in resultTable.AsEnumerable()
select (string)results[attributeList]).Distinct().OrderBy(name => name);




.net-3.5