C# flatten a list of objects-CodePudding

Given the following objects:

public class Order
{
    public int OrderID { get; set; }
    public int TotalPrice { get; set; }
    public List<OrderItem> Items { get; set; }
}

public class OrderItem
{
    public string Name { get; set; }
    public int Price { get; set; }
    public string SKU { get; set; }
}

Right now I have this structure:

[
    {
        "order_id": 1,
        "total_price": 700,
        "items": [
            {
                "name": "cellphone",
                "price": 500,
                "sku": "1s4f"
            },
            {
                "product_name": "airphones",
                "product_price": 200,
                "sku": "1ar4"
            }
        ]
    },
    {
        "order_id": 2,
        "total_price": 5000,
        "products_info": [
            {
                "name": "car",
                "price": 2500,
                "sku": "8y5t"
            },
            {
                "name": "battery",
                "price": 1500,
                "sku": "5g3g"
            },
            {
                "name": "insurance",
                "price": 1000
                "sku": "5r8f"
            }
        ]
    }
]

I want to the first order to be splitted to 2 orders, each one contains one item, and the second order to be splitted to 3 orders, with the same logic. What's the best clean and readable way of doing that?

CodePudding user response：

Gven an IEnumerable<Order> you can use LINQ Select and SelectMany

var result = orders.SelectMany(o => o.Items.Select(i => new Order{
   OrderID = o.OrderID,
   TotalPrice = i.Price,
   Items = new List<OrderItem> {
        new() { Name = i.Name, Price = i.Price, SKU = i.SKU }
   }
});

This will flatten your items into 5 separate orders, each with a single item. I have assumed you wanted the order TotalPrice to match the price of the single item it now has underneath it.

CodePudding user response：

What you can do is changing OrderItem and put a foreign Key in it

    public class OrderItem
{
    public string Name { get; set; }
    public int Price { get; set; }
    public string SKU { get; set; }
    public int OrderId { get; set; }
    public Order Order { get; set; }
}

and then query like this var Items=_context.OrderItem.Tolist();