为什么这个删除列表dosnt的方法工作？ [英] why this remove method of list dosnt work?

问题描述

list1中有一个对象列表。我想如果list1中的每个对象都在list2中，那么该对象将从list2中删除。问题是在删除后，list2仍然包含该对象!!!

There is a list of objects in list1. I want if each object in list1 there was in list2 too then that object will be deleted from list2.the problem is after removing, list2 still contains that object!!!

 foreach (var item in list1)
{
  
if (list2.Any(x => x.Vacationfrom == item.Vacationfrom && x.VacationTo == item.VacationTo && x.WhenIsVac == item.WhenIsVac && x.TheDay == item.TheDay))
                       
        list2.Remove(item);
}

推荐答案

您正在尝试从list2中删除list1中的项目。您必须从list2中找到与list1中的项匹配的实际项并删除它：

You're trying to remove the item that comes from list1 from list2. You would have to find the actual item from list2 that matches the item from list1 and remove that:

foreach (var item in list1)
{
    var item2 = list2.SingleOrDefault(x => x.Vacationfrom == item.Vacationfrom && x.VacationTo == item.VacationTo && x.WhenIsVac == item.WhenIsVac && x.TheDay == item.TheDay);
    if(item2 != null)
        list2.Remove(item2);
}

item 位于 list1 ;不在 list2 。





您可能需要类似<$ c $的东西c> list1 = list1.Except（...）



https://msdn.microsoft.com/en-us/library/bb336390（v = vs.110）的.aspx [< a href =https://msdn.microsoft.com/en-us/library/bb336390(v=vs.110).aspx\"target =_ blanktitle =New Window> ^ ]

item is in list1; not in list2.


You might want something like list1 = list1.Except ( ... )

https://msdn.microsoft.com/en-us/library/bb336390(v=vs.110).aspx[^]

因为

var item

$ b $ c> list2中不存在
，是 list1 的项目。您可以在里面使用for for。

对于 list1 中的每个项目，你在 list2中看起来都是并且，如果 list1 中的当前项目等于 list2 中的当前项目，则删除该项目并打破内部for并转到第一个for的下一个循环。

does not exists in list2, is a list1's item. You can use a for inside a for.
For each item in list1 you look all itens in list2 and, if the current item in list1 is equal the current item in list2, you remove that item and break the internal for and go to the next loop of the first for.

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