private void submit_button_Click(object sender, EventArgs e)
 {
     if (!CheckString.ChechPower(power_textBox.Text.Trim()))
     {
         MessageBox.Show("权限仅限 管理员/进货员/销售员", "权限输入错误");
     }
     else if (name_textBox.Text.Trim().Equals(""))
     {
         MessageBox.Show("用户名不能为空", "用户名输入错误");
     }
     else
     {
         Connector.AddNewSysUser(name_textBox.Text.Trim(), SecurityUnit.EncryptToSHA1(pwd_textBox.Text.Trim()), power_textBox.Text.Trim());
     }
 }