private void BtnAddEmployee(object sender, RoutedEventArgs e)
        {
            Employee emp = new Employee();

            if (!(txtEmpId.Text.Equals("") || (txtLast.Text.Equals("") || txtFName.Text.Equals("") || txtTitle.Text.Equals("") || txtIDNo.Text.Equals("") || txtAddress.Text.Equals("") || txtReportTo.Text.Equals("") || txtEmail.Text.Equals("") || txtPass.Password.Equals(""))))
            {
                emp.EmpID     = Int32.Parse(txtEmpId.Text);
                emp.LastName  = txtLast.Text;
                emp.FirstName = txtFName.Text;
                emp.Title     = txtTitle.Text;
                emp.IDNo      = txtIDNo.Text;
                emp.Address   = txtAddress.Text;
                emp.ReportTo  = Int32.Parse(txtReportTo.Text);
                emp.Email     = txtEmail.Text;
                emp.Username  = txtUserName.Text;
                emp.Password  = txtPass.Password;
                if (cPos.SelectedIndex == 0)
                {
                    emp.EmployeePositionID = 1;
                    MessageBox.Show("Cashier");
                }
                else if (cPos.SelectedIndex == 1)
                {
                    emp.EmployeePositionID = 2;
                    MessageBox.Show("Supervisor");
                }

                if (da.EmailIsValid(txtEmail.Text))
                {
                    if (emp.IDNo.Length == 13)
                    {
                        string msg = da.AddEmployee(emp);

                        MessageBox.Show("" + msg);
                        if (msg.Equals("Employee Added"))
                        {
                            MainWindow mw = Application.Current.Windows.OfType <MainWindow>().FirstOrDefault();
                            if (mw != null)
                            {
                                mw.MainFrame.Content = new ManageEmployees();
                            }
                        }
                    }
                    else
                    {
                        MessageBox.Show("SA ID must be 13 digits long");
                    }
                }
                else
                {
                    MessageBox.Show("Wrong Email");
                }
            }
            else
            {
                MessageBox.Show("All textbox must be full");
            }
        }
        private void BtnAddSupplier(object sender, RoutedEventArgs e)
        {
            if (!(txtsupId.Text.Equals("") || txtCompanyName.Text.Equals("") || txtAddress.Text.Equals("") || txtCity.Text.Equals("") || txtRegion.Text.Equals("") || txtPostCode.Text.Equals("") || txtCountry.Text.Equals("") || txtPhoneNumber.Text.Equals("") || txtEmail.Text.Equals("")))
            {
                Supplier s = new Supplier();

                s.SupplierID  = Int32.Parse(txtsupId.Text);
                s.CompanyName = txtCompanyName.Text;
                s.Address     = txtAddress.Text;
                s.City        = txtCity.Text;
                s.Region      = txtRegion.Text;
                s.PostalCode  = txtPostCode.Text;
                s.Country     = txtCountry.Text;
                s.Phone       = txtPhoneNumber.Text;
                s.Email       = txtEmail.Text;
                if (da.EmailIsValid(txtEmail.Text))
                {
                    string msg = da.AddSupplier(s);

                    MessageBox.Show("" + msg);
                    if (msg.Equals("New Supplier Added"))
                    {
                        MainWindow mw = Application.Current.Windows.OfType <MainWindow>().FirstOrDefault();
                        if (mw != null)
                        {
                            mw.MainFrame.Content = new ManageSuppliers();
                        }
                    }
                }
                else
                {
                    MessageBox.Show("Wrong email please enter correct email");
                }
            }
            else
            {
                MessageBox.Show("All textbox must be full");
            }

            //is knowlegde obtained through observetion  critical tested and expirinmented
        }