private void CreateButton_OnClick(object sender, RoutedEventArgs e)
 {
     try
     {
         var provider = new Context.Context().Providers.Where(t => t.ProviderName == ProviderIdCombo.Text).Select(t => t.ProviderId).First();
         //CrudRepository<Smartphone> crudRepository = new CrudRepository<Smartphone>(new Context.Context());
         //crudRepository.Create(new Smartphone(Int32.Parse(SmartphoneId.Text), SmartphoneName.Text,
         //    Int32.Parse(YearOfIssue.Text), Double.Parse(Cost.Text), provider));
         unitSmartphone.CrudRepository.Create(new Smartphone(Int32.Parse(SmartphoneId.Text), SmartphoneName.Text, Int32.Parse(YearOfIssue.Text), Double.Parse(Cost.Text), provider));
         MessageBox.Show("Done");
     }
     catch (Exception exception)
     {
         MessageBox.Show(exception.Message);
     }//crudRepository.GetWithInclude(t => t.Provider.ProviderName == ProviderIdCombo.Text).First(t=> t.ProviderId)
 }
 public MainWindow()
 {
     InitializeComponent();
     try
     {
         using (Context.Context context = new Context.Context())
         {
             var providers = context.Providers.Select(t => t.ProviderName);
             foreach (var t in providers)
             {
                 ProviderIdCombo.Items.Add(t);
             }
         }
     }
     catch (Exception e)
     {
         MessageBox.Show(e.Message);
     }
 }