private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                if (textBox1.Text == "输入工号" || textBox1.Text == "")
                {
                    DataGridView  data = new DataGridView();
                    employeedao   p    = new employeedao();
                    List <employ> rs   = new List <employ>();
                    rs = p.find_all1();
                    Console.Write(rs);
                    int       i  = 0;
                    DataSet   ds = new DataSet();
                    DataTable dt = new DataTable("Table_New");
                    dt.Columns.Add("工号", typeof(string));
                    dt.Columns.Add("姓名", typeof(string));
                    dt.Columns.Add("联系电话", typeof(String));
                    foreach (employ r1 in rs)
                    {
                        dt.Rows.Add(r1.Employee_number, r1.Employee_name, r1.Phone);
                        i++;
                    }
                    dataGridView1.DataSource = dt;
                }
                else
                {
                    DataGridView data = new DataGridView();
                    employeedao  p    = new employeedao();
                    employ       r1   = p.selectid(textBox1.Text);
                    Console.Write(textBox1.Text);

                    if (r1 == null)
                    {
                        MessageBox.Show("不存在此人");
                    }
                    else
                    {
                        DataSet   ds = new DataSet();
                        DataTable dt = new DataTable("Table_New");
                        dt.Columns.Add("工号", typeof(string));
                        dt.Columns.Add("姓名", typeof(string));
                        dt.Columns.Add("联系电话", typeof(String));
                        dt.Rows.Add(r1.Employee_number, r1.Employee_name, r1.Phone);
                        dataGridView1.DataSource = dt;
                    }
                }
            }
            catch (SystemException)
            {
                MessageBox.Show("操作有误");
            }
        }
        private void employee_purchase_Load(object sender, EventArgs e)
        {
            DataGridView  data = new DataGridView();
            employeedao   p    = new employeedao();
            List <employ> rs   = new List <employ>();

            rs = p.find_all1();
            Console.Write(rs);
            int       i  = 0;
            DataSet   ds = new DataSet();
            DataTable dt = new DataTable("Table_New");

            dt.Columns.Add("工号", typeof(string));
            dt.Columns.Add("姓名", typeof(string));
            dt.Columns.Add("联系电话", typeof(String));
            foreach (employ r1 in rs)
            {
                dt.Rows.Add(r1.Employee_number, r1.Employee_name, r1.Phone);
                i++;
            }
            dataGridView1.DataSource = dt;
        }