private void 签到ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            string name = this.dgvSe.SelectedRows[0].Cells["name1"].Value.ToString();
            if (recordTable.ContainsKey(name))
            {
                MessageBox.Show("已经签到");
            }
            else 
            {
                RecordClass recordSe = new RecordClass();
                recordSe.name = name;
                recordSe.firstTime = DateTime.Now;
                recordTable.Add(name, recordSe);
            }        }        private void 签退ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            DataGridViewRow dr = this.dgvSe.CurrentRow;
            if (dr == null)
            {
                return;
            }
            string name = dr.Cells["name1"].Value.ToString();
            if (recordTable.ContainsKey(name))
            {
                RecordClass rc = recordTable[name];
                rc.secondTime = DateTime.Now();====这一行显示不可调用的system.datetime.now
                MessageBox.Show("签退成功");            }
            else
            {
                MessageBox.Show("没签到不能签退");
            }
        }