Hi i\'ve got 2 data tables (bannedlist,countrylist), both contains list of country names and cods in columns cc and country. I am trying to do a query where i can select cou
You can use the Except() LINQ extension method like this:
var result = full.Except(banned);
However this will work fine with the default comparer of the contained type. Thus if you want to use a specific column like in your example, you might need another approach like:
from r in ccList
where !bannedCCList.Any(b => b["cc"] == r["cc"])
select r;
Using Except() implies the references are the same in both collections, which I think is not the case with Tables, or correct me if I'm wrong.
Except would work if you use it on sequences of the countries:
using System.Linq;
...
var ccList = from c in ds.Tables[2].AsEnumerable()
select c.Field<string>("Country");
var bannedCCList = from c in ds.Tables[1].AsEnumerable()
select c.Field<string>("Country");
var exceptBanned = ccList.Except(bannedCCList);
If you need the full rows where the countries aren't banned, you could try a left outer join:
var ccList = ds.Tables[2].AsEnumerable();
var bannedCCList = ds.Tables[1].AsEnumerable();
var exceptBanned = from c in ccList
join b in bannedCCList
on c.Field<string>("Country") equals b.Field<string>("Country") into j
from x in j.DefaultIfEmpty()
where x == null
select c;
Try this:
var query = ccList.Except(bannedCCList);