强制linq sum返回null [英] Force linq sum to return null

问题描述

我想答案很简单:

List<int?> intList = new List<int?>(){null, null, null};
int? sum = list.Sum();
int sum2 = list.Sum(a => a.HasValue ? a.Value : 0);
int sum3 = list.Sum().Value;

总和总是返回0，为什么根本需要可空值?有没有办法强制linq sum返回null?我在这里想念什么?

Sum is always returning 0, why is nullable needed at all? Is there a way to force linq sum to return null? What am I missing here?

推荐答案

这是

不返回null的原因是它的实现方式-使用int sum = 0;作为结果永远不会返回null.

The reason for not returning null is the way it's implemented - the usage of int sum = 0; as result can never return null.

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