Zachet/DB/Pages/AddChangePage.xaml.cs

using DB.Classes;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

enum CreateState {Create, Update };

namespace DB.Pages
{
    /// <summary>
    /// Логика взаимодействия для AddChangePage.xaml
    /// </summary>
    public partial class AddChangePage : Page
    {
        CreateState state;
        Service service = new Service();
        public AddChangePage()
        {
            InitializeComponent();
            state = CreateState.Create;
        }
        public AddChangePage(int id)
        {
            InitializeComponent();
            state = CreateState.Update;
            service = DataBaseClass.entity.Service.FirstOrDefault(x => x.ID == id);
            TBTitle.Text = service.Title;
            TBCost.Text = service.Cost.ToString();
            BTNDio.Content = "Change";
        }

        private void BTNDio_Click(object sender, RoutedEventArgs e)
        {
            Service check = DataBaseClass.entity.Service.FirstOrDefault(x => x.Title.ToLower() == TBTitle.Text.ToLower());
            if(check != null)
            {
                MessageBox.Show("Такая запись уже есть!");
                return;
            }
            bool flag = true;
            while(flag)
            {
                if(state == CreateState.Create)
                {
                    service.Title = TBTitle.Text;
                    service.Cost = Convert.ToDecimal(TBCost.Text);
                    DataBaseClass.entity.Service.Add(service);
                }
                else
                {
                    service.Title = TBTitle.Text;
                    service.Cost = Convert.ToDecimal(TBCost.Text);
                }
                if(state  != CreateState.Update)
                {
                    MessageBox.Show("Добавление!");
                }
                else
                {
                    MessageBox.Show("Изменение!");
                }
                DataBaseClass.entity.SaveChanges();
                ListViewPage listViewPage = new ListViewPage();
                listViewPage.LVService.ItemsSource = DataBaseClass.entity.Service.ToList();
                FrameClass.MainFrame.Navigate(listViewPage);
                flag = false;
            }
        }
    }
}