在对象的列表替换对象 [英] Replace a object in a list of objects

问题描述

在C＃中，如果我有一个列表< T> ，我有类型的对象 T ，我怎么能在更换特定项目的列表< T> 同类型的对象 T

In C#, if I have a List<T>, and I have an object of type T, how can I replace a specific item in the List<T> with the object of type T?

下面是我曾尝试：

List<CustomListItem> customListItems = new List<CustomListItem>();
CustomListItem customListItem1 = new CustomListItem() { name = "Item 1", date = DateTime.MinValue};
CustomListItem customListItem2 = new CustomListItem() { name = "Item 2", date = DateTime.MinValue };
CustomListItem customListItem3 = new CustomListItem() { name = "Item 3", date = DateTime.MinValue };

customListItems.Add(customListItem1);
customListItems.Add(customListItem2);
customListItems.Add(customListItem3);

CustomListItem newCustomListItem = new CustomListItem() { name = "Item 4", date = DateTime.Now };

customListItem2 = customListItems.Where(i=> i.name == "Item 2").First();
customListItem2 = newCustomListItem;

在上面的代码，我想替换 customListItem2 与 newCustomListItem 。

In the above code, I want to replace the customListItem2 with the newCustomListItem.

我必须删除列表中的项目，然后插入新物品？我不能做 customListItem2 = newCustomListItem ？

Do I have to remove the item in the list, and then insert the new item? Can I not do a simple assignment of customListItem2 = newCustomListItem?

什么是替换项目的最有效的方法的简单任务与其他项目的列表？

What is the most efficient way of replacing an item in a list with another item?

在此先感谢

推荐答案

你必须更换的项目，而不是 customListItem2 的价值。只需更换如下：

You have to replace the item, not the value of customListItem2. Just replace following:

customListItem2 = customListItems.Where(i=> i.name == "Item 2").First();
customListItem2 = newCustomListItem;

通过这样的：

customListItem2 = customListItems.Where(i=> i.name == "Item 2").First();
var index = customListItems.IndexOf(customListItem2);

if(index != -1)
    customListItems[index] = newCustomListItem;

编辑：

由于罗马R. 在评论中所述，您可以替换。凡（谓语）。首先（）通过一个简单的第一（谓语）：

As Roman R. stated in a comment, you can replace the .Where(predicate).First() by a simple First(predicate):

customListItem2 = customListItems.First(i=> i.name == "Item 2");

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