DataGridView Datatable Copy-Keep-Add-Update rows

[opendoor8]

Hi,

I have a datagridview with records completed by datatable dt:
This datatable has 20 columns with 1 identity column

dataGridView1.D ataSource = dt;


I need to solve next problems:
1. Select rows filtered by column[2]
2. Keep these records
3. Add exactly the same records below but update column[2] with different value (so we’ll have twice more records)

I used next code for copying from one datatable to another but stack how to add/update rows

DataTable dtSource = ((DataTable)dataGridView1.DataSource);

DataTable dtTarget = new DataTable();
dtTarget = ((DataTable)dataGridView1.DataSource).Clone();

DataRow[] rowsToCopy;

rowsToCopy = ((DataTable)dataGridView1.DataSource).Select("DrawingNo='DM-3012'
 ");

foreach (DataRow temp in rowsToCopy)
{
	dtTarget.ImportRow(temp);
}

dt = dtTarget;

Thanks,