private void button1_Click(object sender, EventArgs e)
        {
            Cursor.Current  = Cursors.WaitCursor;
            button1.Enabled = false;
            button2.Enabled = false;
            ATINChamCongEntities context = new ATINChamCongEntities();

            if (dataGridView1.Rows.Count < 1)
            {
                return;
            }
            try
            {
                foreach (DataGridViewRow row in dataGridView1.Rows)
                {
                    if (row.Cells[0].Value == null)
                    {
                        continue;
                    }
                    if ((bool)row.Cells[0].Value == true)
                    {
                        context.spDeleteChamCongChiTietByNguoi((row.DataBoundItem as Nguoi).MaNguoi, dateEdit1.DateTime, dateEdit2.DateTime, checkBox1.Checked);
                    }
                }
                MessageBox.Show("Xóa dữ liệu chấm công thành công!");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            Cursor.Current  = Cursors.Default;
            button1.Enabled = true;
            button2.Enabled = true;
        }