private void Clicked_NewCategory(object sender, RoutedEventArgs e)
 {
     this._ModeEnabled_workWithSparePartCategories = true;
     this._Mode_workWithCategory    = WorkWithEntityMode.Adding;
     this._sparePartCategoryForWork = new SparePartCategory();
     this._Flyout_ForSparePartCategories.DataContext = this._sparePartCategoryForWork;
 }
        private void Clicked_ChangeCategory(object sender, RoutedEventArgs e)
        {
            if (this._SelectedSparePartCategory != null)
            {
                this._ModeEnabled_workWithSparePartCategories = true;
                this._Mode_workWithCategory = WorkWithEntityMode.Change;

                this._sparePartCategoryForWork = _SelectedSparePartCategory;
                this._Flyout_ForSparePartCategories.DataContext = this._sparePartCategoryForWork;
            }
            else
            {
                MessageBox.Show("Выберите категорию");
            }
        }