LINQ query for this scenario

Question

I have these 2 interfaces:

public interface IShipment
{
    IEnumerable<IShippedItem> Contents { get; }
    string InvoiceNumber { get; }
}

public interface IShippedItem
{
    string ProductCode { get; }
    int Quantity { get; }
}

Now, I am trying to write a LINQ statement to get me just a list of ProductCode.

How to go about this?

IEnumerable<IShipment> shipments = GetShipments();
var productCodeList = from shipment in shipment
                      ???????

Answer 1

You can use SelectMany to flatten your contents then just use Select and get the ProductCode for each IShippedItem.

var productCodes = shipments
                   .SelectMany(x => x.Contents)
                   .Select(x => x.ProductCode)
                   .ToList();