transfering rows between datatables

Question

  I have 2 datagridviews.  I need to transfer a single selected row from one to another

 

 I have used this code:-

private void button4_Click(object sender, EventArgs e)
       {
           List<Object> TList = new List<object>();
           foreach(DataGridViewRow row in dataGridView1.SelectedRows)
           {
               TList.Add(row.DataBoundItem);
               dataGridView2.DataSource = TList;
           }
       }

 it copies a single row from datagridview1 to datagridview2 .

but when i try to add another row , it replaces the current row in  datagridview2.

any solution??