Question

首先，阅读下面的类代码。在那里，您将找到一个名为CommonId的属性，该属性在Item类和ItemGallery中很常见，并且都具有匹配的int值。现在，检查作为主控制台程序的Program类。在这里，我将一些数据添加到两个类中以作为示例。在主程序类的底部，我尝试遍历每个Item并找到与ItemGallery commonId匹配的commonId，如果匹配的commonId则在ItemGallery中从其匹配的Item ID复制ItemId。主要目标是-只需将副本从Item类ID复制到具有相匹配commonId的ItemGallery ItemId。怎么做？我已经尝试过像波纹管一样的foreach，但这不是正确的方法。

主程序类：

class Program {
        static void Main(string[] args) {
            List<Item> MyItemList = new List<Item>();
            MyItemList.Add(new Item {
                CommonId = 502,
                Id = 3,
                Link = "some string1"
            });

            MyItemList.Add(new Item {
                CommonId = 502,
                Id = 4,
                Link = "some string2"
            });

            MyItemList.Add(new Item {
                CommonId = 502,
                Id = 5,
                Link = "some string3"
            });

            MyItemList.Add(new Item {
                CommonId = 506,
                Id = 6,
                Link = "some string4"
            });

            List<ItemGallery> MyitemGalleries = new List<ItemGallery>();
            MyitemGalleries.Add(new ItemGallery {
                CommonId = 502,
                Link = "",
            });
            MyitemGalleries.Add(new ItemGallery {
                CommonId = 502,
                Link = "",
            });
            MyitemGalleries.Add(new ItemGallery {
                CommonId = 502,
                Link = "",
            });

            foreach (var _MyItemList in MyItemList) {
                MyitemGalleries.FirstOrDefault().ItemId = _MyItemList.Where(x => x.CommonId == MyitemGalleries.CommonId).FirstOrDefault().Id;
            }
            Console.ReadKey();
        }
    }

班级：

class Item {
    public int Id { get; set; }//this id need to set to ItemGallery ItemId matching their CommonId
    public int CommonId { get; set; }
    public string Link { get; set; }
}

class ItemGallery {
    public int ItemId { get; set; }
    public int CommonId { get; set; }
    public string Link { get; set; }
}

Answer 1

如果我了解您并且不考虑任何其他问题，则没有几种方法可以做到这一点。但是，简单的foreach和FirstOrDefault应该可以

foreach (var gallery in MyitemGalleries) 
{
    var item = _MyItemList.FirstOrDefault(x => x.CommonId == gallery.CommonId);
    // note if there are none we choose not to do anything, or grab the first
    if(item == null)
       continue;

    gallery.ItemId = item.Id;
}

复制匹配ID的值

1 个答案: