DataTable dt = new DataTable("Book");
...
..
// create a new row
DataRow dr = dt.NewRow();

// This will copy the 3rd row into new DataRow object 'dr'
dr.ItemArray = dt.Rows[2].ItemArray;

DataTable dt = new DataTable("Book");
...
..

// This will copy the 3rd row into new DataRow object 'dr'
DataRow dr = dt.NewRow();
for (int j = 0; j < dt.Columns.Count; j++)
{
    dr[j] = dt.Rows[2][j];
}