LINQ查詢此方案

Question

我有這2個接口：

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

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

現在，我想寫一個LINQ聲明讓我只是一個ProductCode列表。

如何去做這件事？

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

Answer 1

您可以使用SelectMany扁平化你的內容就用Select並得到ProductCode每個IShippedItem。

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

Answer 2

是我的錯，我提交的早期，那就是：

from shipment in shipments 
from shippedItem in shipment.Contents 
select shippedItem.ProductCode