Abp 仓储的讨论

ABP的文档示例中，是这样的：

public class TaskAppService : ApplicationService, ITaskAppService
{
    private readonly IRepository<Task> _taskRepository;

    public TaskAppService(IRepository<Task> taskRepository)
    {
        _taskRepository = taskRepository;
    }

　　如果这个AppService 需要多个 IRepository 呢？ 一个一个注入吗？

查看仓储这个接口，发现是瞬时的生命周期。 每个仓储接口的实现类中，都会有Context。 这样一个请求，需要实例化这么多的Context？

另外从应用角度上看，每一个接口确实实现应该有独立的Context。Context的生命周期应该是Scope的

namespace Microsoft.Extensions.DependencyInjection
{
    //
    // 摘要:
    //     /// Extension methods for setting up Entity Framework related services in an
    //     Microsoft.Extensions.DependencyInjection.IServiceCollection. ///
    public static class EntityFrameworkServiceCollectionExtensions
    {
        //
        // 摘要:
        //     /// Registers the given context as a service in the Microsoft.Extensions.DependencyInjection.IServiceCollection.
        //     /// You use this method when using dependency injection in your application,
        //     such as with ASP.NET. /// For more information on setting up dependency injection,
        //     see http://go.microsoft.com/fwlink/?LinkId=526890. ///
        //
        // 参数:
        //   serviceCollection:
        //     The Microsoft.Extensions.DependencyInjection.IServiceCollection to add services
        //     to.
        //
        //   optionsAction:
        //     ///
        //     /// An optional action to configure the Microsoft.EntityFrameworkCore.DbContextOptions
        //     for the context. This provides an /// alternative to performing configuration
        //     of the context by overriding the /// Microsoft.EntityFrameworkCore.DbContext.OnConfiguring(Microsoft.EntityFrameworkCore.DbContextOptionsBuilder)
        //     method in your derived context. ///
        //     ///
        //     /// If an action is supplied here, the Microsoft.EntityFrameworkCore.DbContext.OnConfiguring(Microsoft.EntityFrameworkCore.DbContextOptionsBuilder)
        //     method will still be run if it has /// been overridden on the derived context.
        //     Microsoft.EntityFrameworkCore.DbContext.OnConfiguring(Microsoft.EntityFrameworkCore.DbContextOptionsBuilder)
        //     configuration will be applied /// in addition to configuration performed here.
        //     ///
        //     ///
        //     /// In order for the options to be passed into your context, you need to expose
        //     a constructor on your context that takes /// Microsoft.EntityFrameworkCore.DbContextOptions`1
        //     and passes it to the base constructor of Microsoft.EntityFrameworkCore.DbContext.
        //     ///
        //     ///
        //
        //   contextLifetime:
        //     The lifetime with which to register the DbContext service in the container.
        //
        //   optionsLifetime:
        //     The lifetime with which to register the DbContextOptions service in the container.
        //
        // 类型参数:
        //   TContext:
        //     The type of context to be registered.
        //
        // 返回结果:
        //     /// The same service collection so that multiple calls can be chained. ///
        public static IServiceCollection AddDbContext<TContext>([JetBrains.Annotations.NotNull] this IServiceCollection serviceCollection, [JetBrains.Annotations.CanBeNull] Action<DbContextOptionsBuilder> optionsAction = null, ServiceLifetime contextLifetime = ServiceLifetime.Scoped, ServiceLifetime optionsLifetime = ServiceLifetime.Scoped) where TContext : DbContext
        {
            return serviceCollection.AddDbContext<TContext, TContext>(optionsAction, contextLifetime, optionsLifetime);
        }

我们使用最原始的写法的话，应该只用一个Context.并且执行的逻辑也最清晰。

那这里的原因就是，一个AppService 中注入多个仓储接口是不合理的，这里应该使用一个仓储接口的Context 来引用到别的实体。或者在Domain层处理这些，但本质还是一样的。

 

2，在上面的例子中，Application 或Domain 里，经常会写Insert（entity）或InsertAndGetId（entity）

他们源码：

 public override TEntity Insert(TEntity entity)
        {
            return Table.Add(entity).Entity;
        }


public override TPrimaryKey InsertAndGetId(TEntity entity)
        {
            entity = Insert(entity);
            if (entity.IsTransient())
            {
                Context.SaveChanges();
            }

            return entity.Id;
        }

可以看出，InsertAndGetId是立即提交到数据库了，如果这个UOW 异常，还需要rollback。