返回一个元素，从迭代器块 - 迭代器不能包含return语句 [英] Returning a single element from an iterator block - Iterator cannot contain return statement

问题描述

让我们说我有下面的方法。在某些来到

Let's say I have the following method. In some came

    public IEnumerable<ValidationResult> Validate(UserLoginCommand command)
    {
        User user = userRepository.Get(u => u.Email == command.UserEmail);
        if(user != null)
        {
            if(!user.Activated)
            {
                return new IEnumerable<ValidationResult>() {new ValidationResult("NotActived", Resources.UserNotActivated)};
            }

            if(user.IsPasswordIncorrent)
            {

                yield return new ValidationResult("IncorrectPassword", Resources.IncorrentPassword);

            }

        }
    }

实际情况实际上是一个有点复杂，但我已经留下了很多出用于说明目的。

The actual situation is actually a bit more complex but I've left a lot out for illustration purposes.

点是在某些情况下，我想迭代器继续收集多个错误......但在其他情况下，有一个致命的错误，我只是想返回一个错误，但它不会让我：

The point is in some cases, I want to iterator to continue collecting multiple errors...but in other cases there is a fatal error and I only want to return a single error but it will not let me:

Iterator cannot contain return statement 

我应该怎么办？

What should I do?

推荐答案

如果你只是想返回大小为一的集合，你可以这样做：

If you just want to return a collection of size one, you can do this:

if(!user.Activated)
{
  yield return new ValidationResult("NotActived", Resources.UserNotActivated);
  yield break;
}

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