Winform 批量删除DataGridView

 private void checkBox1_CheckedChanged(object sender, EventArgs e)      {        foreach (DataGridViewRow dr in this.dgv_client.Rows)        {          dr.Cells["Column8"].Value = checkBox1.Checked;// checkBox列        }      }      private void bt_delete_Click(object sender, EventArgs e)      {        for (int i = dgv_client.Rows.Count - 1; i >= 0;i-- )        {          if (dgv_client.Rows[i].Cells["Column8"].Value == null)          {            continue;          }          if ((bool)dgv_client.Rows[i].Cells["Column8"].Value == true)          {            dgv_client.Rows.Remove(dgv_client.Rows[i]);// 替换成sql语句          }        }      }