Question

我有以下代码部分，其中SavePersonAsync方法正在调用3个外部方法，并且任何人都可以告诉我async / await方法的实现是否正确实现。是否没有正确实现async / await的任何调用链？

    public PersonService(IPersonDbService personDbService,
        IPersonEntityToPersonModelMapper personEntityToPersonModelMapper,
        IPersonModelToPersonEntityMapper personModelToPersonEntityMapper)
    {
        _personDbService = personDbService;
        _personEntityToPersonModelMapper = personEntityToPersonModelMapper;
        _personModelToPersonEntityMapper = personModelToPersonEntityMapper;
    }


    public async Task<IEnumerable<PersonModel>> SavePersonAsync(IEnumerable<PersonModel> personsModel)
    {
        var personsEntity = await _personModelToPersonEntityMapper.MapPersonModelToPersonEntityAsync(personsModel);

       var savedPersons = await _personDbService.SavePersonAsync(personsEntity.First()); // Currently only alow one person at a time, later it will allow to save a collection of persons

        return await _personEntityToPersonModelMapper.MapPersonEntityToPersonModelyAsync(new List<PersonEntity>
        {
            savedPersons
        });
    }
}

public class PersonEntityToPersonModelMapper : IPersonEntityToPersonModelMapper
{
    public async Task<IEnumerable<PersonModel>> MapPersonEntityToPersonModelyAsync(
        IEnumerable<PersonEntity> personsEntity)
    {
        if (personsEntity.NullOrEmpty())
            return await Task.FromResult(Enumerable.Empty<PersonModel>());

        return await Task.FromResult(personsEntity.Select(personEntity => new PersonModel
        {
            FirstName = personEntity.FirstName,
            LastName = personEntity.LastName              
        }));
    }
}

public class PersonModelToPersonEntityMapper : IPersonModelToPersonEntityMapper
{
    public async Task<IEnumerable<PersonEntity>> MapPersonModelToPersonEntityAsync(IEnumerable<PersonModel> personsModel)
    {
        if (personsModel.NullOrEmpty())
            return await Task.FromResult(Enumerable.Empty<PersonEntity>());

        return await Task.FromResult(personsModel.Select(personModel => new PersonEntity
        {                
            FirstName = personModel.FirstName,
            LastName = personModel.LastName               
        }));
    }
}

Answer 1

从async await的定义中，当你编写等待时，流将开始顺序，因为你需要在下一个语句中使用输出，那么在你的情况下没有太多使用async await

要弄清楚它是如何运作的假设你必须使用方法调用，它可以工作异步，你的代码就像：

Var a = GetMethodA（）;

Var b = GetMethodB（）;

等待a;

等待b;

在这种情况下，您的方法将异步工作

将异步方法的输出链接为另一个异步方法的输入c＃

1 个答案: