将foreach循环减少为linq查询

Question

var inventionIds = new List<int>();
List<ProductRemunerationReportingPeriodLink> productRemunerationReportingList = 
        GetAllProductRemunerationReportingPeriodByProductId(productId);

foreach (var rptPeriod in productRemunerationReportingList)
{
    var inventionsList = rptPeriod.Inventions;
    foreach (var link in inventionsList)
    {
                int id  = link.Invention.InventionId;
                inventionIds.Add(id);
    }
}

return inventionIds;

我想最小化两个for循环任何一个请为此提供一个nhibernate linq查询。任何帮助都是非常明确的。

Answer 1

使用原始变量名称：

var inventionIds =
    productRemunerationReportingList.SelectMany(rptPeriod => rptPeriod.Inventions)
                                    .Select(ProductRemunerationReportingPeriodInvention => ProductRemunerationReportingPeriodInvention.Invention.InventionId)
                                    .ToList();

与更好的命名相同：

var inventionIds = GetAllProductRemunerationReportingPeriodByProductId(productId)
                     .SelectMany(p => p.Inventions)
                     .Select(i => i.Invention.InventionId)
                     .ToList();

提示：变量名的长度应对应于使用变量的范围。全局可访问的变量应具有良好的描述性名称。在像lambda这样的短范围内使用的变量应该有很短的名称。

Answer 2

List<int> inventionIds = (from rptPeriod in productRemunerationReportingList 
from ProductRemunerationReportingPeriodInvention in rptPeriod.Inventions
select ProductRemunerationReportingPeriodInvention.Invention.InventionId).ToList<int>();