If you’re like me (I hope not too much like me) you probably find yourself using DataTables to hold lots of data for fast, flexible in memory usage. I get asked often, “how can I copy a DataTable?” or even more often, “how can I copy a DataTable, but change the sort or modify the rows”. Look no further. Below you’ll find my thoughts:
Example one (a simple copy with a sort difference):
//datatable
var table = new DataTable();
//get some data
using (var conn = new SqlConnection(yourSqlConn))
{
var comm = new SqlCommand(@"select * from someTable order by someColumn", conn);
comm.CommandType = CommandType.Text;
conn.Open();
var data = comm.ExecuteReader();
table.Load(data);
}
//bind to some control (repeater)
rptFirstList.DataSource = table;
rptFirstList.DataBind();
//second table
var secondTable = new DataTable();
secondTable = table.Copy();
secondTable.DefaultView.Sort = "someOtherColumn";
//bind second
rptSecondList.DataSource = secondTable;
rptSecondList.DataBind();
Example two (creating a copy of the table but allowing a filter, sort or other criteria):
//datatable
var table = new DataTable();
//get some data
using (var conn = new SqlConnection(yourSqlConn))
{
var comm = new SqlCommand(@"select * from someTable order by someColumn", conn);
comm.CommandType = CommandType.Text;
conn.Open();
var data = comm.ExecuteReader();
table.Load(data);
}
//bind to some control (repeater)
rptFirstList.DataSource = table;
rptFirstList.DataBind();
//second table
var secondTable = new DataTable();
//clone to get columns - NO data is copied
secondTable = table.Clone();
//loop through rows and import based on filter
foreach (DataRow dr in table.Select("someColumn = 'value'","someColumnToSort")) {
secondTable.ImportRow(dr);
}
//bind second
rptSecondList.DataSource = secondTable;
rptSecondList.DataBind();
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So for some reason you have the need to use 
Chris Bitting 
