DataGridView操作之获取checkbox列选中行数

int selected=0;
private void dgvArchivesData_CellContentClick(object sender, DataGridViewCellEventArgs e)
{
      for (int i = 0; i < dgvArchivesData.Rows.Count; i++)
      {
           if ((bool)dgvArchivesData.Rows[i].Cell                                [0].EditedFormattedValue == true)
           {
                selected++; 
           }

      }
      return  selected;
}