请问您preFER看？

What would you prefer to see?

try
{
  var item = list.Single(x => x.HasFoo);
}
catch(InvalidOperationException e)
{
  throw new InvalidOperationException("Exactly one item with foo expected, none found", e);
}

或者

var item = list.SingleOrDefault(x => x.HasFoo);
if (item == null)
      throw new InvalidOperationException("Exactly one item with foo expected, none found");

什么是最好的做法吗？哪一个做的异常的详细COM prehensible？

What's the best practice here? Which one makes the exception more comprehensible?

推荐答案

Use SingleOrDefault() if 0 or 1 items are expected Use Single() if 1, not 0 or 2 and more, item is expected

另外请记住，有一些可能出现的情况：

Also keep in mind that there are a number of possible scenarios:

和

和不要忘了一（）， FirstOrDefault（）和任何（）