c# - 过滤掉 Linq 中的空值

Question

我有以下(工作)代码。它非常不优雅，我认为它可以仅使用 Linq 进行重构，从而避免 foreach 循环并必须依赖外部 List<>。这个怎么做？谢谢

  List<string> answerValues = new List<string>();
  foreach (Fillings filling in fillings)
  {
      string answer = filling.Answers.Where(a => a.Questions == question)
          .Select(a => a.Answer).FirstOrDefault();
      if (!string.IsNullOrEmpty(answer)) answerValues.Add(answer);
  }

Answer 1

IEnumerable<string> answerValues = fillings
                                    .SelectMany(f => f.Answers)
                                    .Where(a => a.Questions == question)
                                    .Select(a => a.Answer)
                                    .Where(ans => !string.IsNullOrEmpty(ans));

或者如果您需要一个列表:

IList<string> answerValues = fillings
                                    .SelectMany(f => f.Answers)
                                    .Where(a => a.Questions == question)
                                    .Select(a => a.Answer)
                                    .Where(ans => !string.IsNullOrEmpty(ans))
                                    .ToList();