遍历列表时可以修改列表吗？ [英] Possible to modify a List while iterating through it?

问题描述

我有以下内容：

foreach (var depthCard in depthCards)
{
    var card = InternalGetCard(db, depthCard.CardId);
    var set = InternalGetSet(db, (int)card.ParentSetId);
    var depthArray = InternalGetDepthArrayForCard(db, set.SetId);
    foreach (var cardToUpdate in set.Cards)
    {
        // do stuff
        SaveChanges(db);
        depthCards.Remove(depthCardToUpdate); // since I already took care of it here, remove from depthCards
    }
}

但这不起作用，因为我正在循环中间修改集合。我的问题是…是否存在某种允许这种访问方式的集合？

This isn't working though because I'm modifying the collection in the middle of a loop. My question is… is there some type of collection that does allow this type of access?

我不想 ToList（） depthCards ，因为我已经有了它们，并且我想要在迭代时修改该列表。

I don't want to ToList() the depthCards because I already have them and I want to modify that list as I'm iterating. Is it possible?

推荐答案

可能的方法是向后迭代：

It's possible, the trick is to iterate backwards:

for (int i = depthCards.Count - 1; i >= 0; i--) {
  if (depthCards[i] == something) { // condition to remove element, if applicable
     depthCards.RemoveAt(i);
  }
}

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