接口中定义异步的方法

我定义了如下接口引出错误:

 public interface INewsCategoryRepository    {
        void CreateNewsCategory(NewsCategory newsCategory);
    }

然后用如下类实现了上述接口

public async void CreateNewsCategory(NewsCategory newsCategory)
 {
      var db = dbContext as NewsEFCoreContext;
      await db.Categories.AddAsync(newsCategory);
  }

于是问题出现了:

public class AddNewsCategoryUseCase
    {
        private readonly IRepository repository;
        private readonly INewsCategoryRepository newsCategoryRepository;
        public AddNewsCategoryUseCase(IRepository argRepository, INewsCategoryRepository argNewsCategoryRepository)
        {
            this.repository = argRepository;
            this.newsCategoryRepository = argNewsCategoryRepository;
        }
        /// <summary>
        /// 添加新的新闻
        /// </summary>
        /// <param name="addNewsCategoryDto"></param>
        public  async void AddNewsCategory(AddNewsCategoryDto addNewsCategoryDto)
        {
            NewsCategory newsCategory = addNewsCategoryDto.ToNewsCategory();
            try
            {
                using (repository)
                {
                    //newsCategoryRepository 是接口成员 其返回类型是void 没办法使用await--------------------------！！！
                    await newsCategoryRepository.CreateNewsCategory(newsCategory);
                    repository.Commit();
                }
            }
            catch (Exception ex)
            {

                throw ex;
            }
            

        }
    }

截图如下:

正确的办法应该是:不能将接口方法定义为void 而应该定义为Task。（没有返回值就用Task，有返回值就用Task<T>）

public interface INewsCategoryRepository
    {
        Task CreateNewsCategory(NewsCategory newsCategory);
    }

实现类如下:

public async Task CreateNewsCategory(NewsCategory newsCategory)
        {
            var db = dbContext as NewsEFCoreContext;
            await db.Categories.AddAsync(newsCategory);
        }

调用这个方法如下:

 public class AddNewsCategoryUseCase
    {
        private readonly IRepository repository;
        private readonly INewsCategoryRepository newsCategoryRepository;
        public AddNewsCategoryUseCase(IRepository argRepository, INewsCategoryRepository argNewsCategoryRepository)
        {
            this.repository = argRepository;
            this.newsCategoryRepository = argNewsCategoryRepository;
        }
        /// <summary>
        /// 添加新的新闻
        /// </summary>
        /// <param name="addNewsCategoryDto"></param>
        public  async Task AddNewsCategory(AddNewsCategoryDto addNewsCategoryDto)
        {
            NewsCategory newsCategory = addNewsCategoryDto.ToNewsCategory();
            try
            {
                using (repository)
                {
                    //没问题------------------！！！
                    await newsCategoryRepository.CreateNewsCategory(newsCategory);
                    repository.Commit();
                }
            }
            catch (Exception ex)
            {

                throw ex;
            }
            

        }
    }

截图:

 参考文章:异步编程中的最佳做法 https://msdn.microsoft.com/zh-cn/magazine/jj991977.aspx?f=255&MSPPError=-2147217396