añadir en la primera fila una celda de la fila 2 de un datagridview

void addRow()
{
     while (dataGridView1.Rows.Count > 0)
     {
           dataGridView1.Rows.RemoveAt(0);
     }
     while (dataGridView2.Rows.Count > 0)
     {
          dataGridView1.Rows.Add(dataGridView2.Rows[0].Cells[0].Value.ToString(), dataGridView2.Rows[0].Cells[1].Value.ToString());
          dataGridView2.Rows.RemoveAt(0);
     }
}