OOOWriteAndClear/OOO_WriteAndClear/DBModels/OrderPartialClass.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Media;

namespace OOO_WriteAndClear.DBModels
{
    public partial class Order
    {
        public decimal OrderCost => 
            OrderProducts.Sum(a=> a.ProductArticleNumberNavigation.CurrentPrice * a.ProductAmount);

        public decimal OrderCostWithoutDiscount =>
            OrderProducts.Sum(a => a.ProductArticleNumberNavigation.ProductCost * a.ProductAmount);

        public decimal OrderDiscount => OrderCostWithoutDiscount - OrderCost;

        public decimal OrderDiscountPercent => 1 - (OrderCost / OrderCostWithoutDiscount);

        public SolidColorBrush OrderBackGround
        {
            get
            {
                SolidColorBrush brush = (SolidColorBrush)new BrushConverter().ConvertFrom("#20b2aa");
                foreach (var item in OrderProducts)
                {
                    if (item.ProductArticleNumberNavigation.ProductQuantityInStock == 0)
                    {
                        brush = (SolidColorBrush)new BrushConverter().ConvertFrom("#ff8c00");
                        break;
                    }
                    if (item.ProductArticleNumberNavigation.ProductQuantityInStock <= 3)
                    {
                        brush = (SolidColorBrush)new BrushConverter().ConvertFrom("#ffffff");
                        break;
                    }
                }
                return brush;
            }
        }
    }
}