Question

I have a DataTable with values:

ID  NameID  Name
1   1       qwe
2   2       ert  
3   2       ert  
4   3       dffg 
5   3       dffg

I want to get a DataTable containing distinct rows like this:

ID  NameID  Name
1   1       qwe
2   2       ert
4   3       dffg 

How can this be achieved using LINQ or other?

Answer 1

var rows = tbl.AsEnumerable().Select(row => row).ToList();
tbl = new DataTable();
tbl.Columns.Add("ID", typeof(Int32));
tbl.Columns.Add("NameID", typeof(Int32));
tbl.Columns.Add("Name", typeof(String));

rows.GroupBy(r => r.Field<int>("NameID"))                
    .Select(rr => rows.First(rw => rw.Field<Int32>("NameID") == rr.Key))
    .ToList()
    .ForEach(rname => tbl.Rows.Add(new object []
        {                                                 
            rname.Field<Int32>("ID"),
            rname.Field<Int32>("NameID"),
            rname.Field<String>("Name"),                    
        }));

---

Test data setup:

DataTable tbl = new DataTable();
tbl.Columns.Add("ID", typeof (Int32));
tbl.Columns.Add("NameID", typeof (Int32));
tbl.Columns.Add("Name", typeof (String));

tbl.Rows.Add(new object[] { 1, 1, "qwe" });
tbl.Rows.Add(new object[] { 2, 2, "ert" });
tbl.Rows.Add(new object[] { 3, 2, "ert" });
tbl.Rows.Add(new object[] { 4, 3, "dffg" });
tbl.Rows.Add(new object[] { 5, 3, "dffg" });