Question

What’s the most efficient way of filtering DataRows in a DataTable? I have a list of integers and want to retrieve all rows (and eventually create a DataTable from them) which match the integers in the list. I’m currently using the code below, but it’s quite slow. Am I missing a more efficient way?

foreach (var i in integerlist)
{
     DataRow dr = (from row in originalDataTable.AsEnumerable()
                   where row.Field<int>("urlID") == i
                   select row).FirstOrDefault<DataRow>();

     if (dr!= null)
     {
          newDataTable.Rows.Add(dr);
     }
}

Answer 1

I suggest you to try to do vice versa.

foreach (var row in originalDataTable)
{

    if(integerList.Contains( (int)row["urlID"]))
       newDataTable.ImportRow(row)
}

It makes even more sense if you have more rows in dataset then integers in your int collection.
Hope it helps 🙂