在循环期间修改集合，但无法将其设置为C#

Collection being modified during loop when there is no way it can be C#

以下代码的foreach语句引发一个InvalidOperationException，表示"集合已修改"。枚举操作无法执行。"我看不出这是怎么可能的，因为颜色在初始化之后是无法修改的。

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Dictionary<Color, int> colorDictionary = new Dictionary<Color, int>();
//Put stuff in colorDictionary...
int currentBest = 257;
Color replaceColor = Color.Empty;
Dictionary<Color, int>.KeyCollection colors = colorDictionary.Keys;
foreach (Color c in colors)
{
if (colorDictionary[c] == 0)
{
continue;
}
if (ColorDistance(color, c) < currentBest)
{
replaceColor = c;
colorDictionary[c]--;
}
}

I don't see how this is possible, seeing as colors can never be modified after it's initialization.

这是字典键上的视图…你在修改字典：

1	colorDictionary[c]--;

诚然，这并不是在添加或删除任何键，而是在修改字典，而键枚举器基本上对此很敏感。

最简单的修复方法就是创建一个副本：

1	IEnumerable<Color> colors = colorDictionary.Keys.ToList();