private void buttonSearch_Click(object sender, EventArgs e) //ok
        {
            int      searchEmpId = Convert.ToInt32(textBoxSearchId.Text);
            Employee emp         = new Employee();

            emp = emp.SearchEmployeeById(searchEmpId);
            if (emp != null)
            {
                textBoxEmployeeId.Text = (emp.EmployeeId).ToString();
                textBoxFirstName.Text  = emp.FirstName;
                textBoxLastName.Text   = emp.LastName;
                textBoxJobTitle.Text   = emp.JobTitle;
                textBoxUserType.Text   = emp.UserType;
                textBoxPassword.Text   = emp.Password;
                textBoxEmail.Text      = emp.Email;
                textBoxSearchId.Clear();
            }
            else
            {
                MessageBox.Show("Employee not found!");
                textBoxSearchId.Clear();
            }
        }