在数据访问层中获取Db上下文 [英] Get Db context inside data access layer

问题描述

我正在尝试解决EF-Core的一些问题.
我使用MVC Core应用程序中的启动代码来初始化db上下文.
这是我的数据库上下文:

I have some problems with EF-Core that I'm trying to figure out.
I use the startup code in the MVC Core application to initalize the db context.
This is my DB context:

public class AccountsDBContext : DbContext
{
    public AccountsDBContext(DbContextOptions<AccountsDBContext> options)
        :base(options)
    {

    }

    // ...

}

启动代码:

 public void ConfigureServices(IServiceCollection services)
 {
        // Inject the account db
        services.AddDbContext<AccountsDBContext>(options =>
           options.UseMySQL(Configuration.GetConnectionString("AccountsStore")));

        // ...

在所有示例中，我都看到数据库上下文是通过构造函数传递到控制器的(我假设通过依赖注入)，然后从那里传递到其他实体\层.

In all the exampes I see the DB Context is a delivered via the constructor to the controller (I assume by dependency injection) and from there on to other entities\ layers.

 [Route("api/[controller]")]
 public class AccountsController : Controller
 {
    private AccountsDBContext _db;

    public AccountsController(AccountsDBContext context)
    {
        this._db = context;
    }

但是，我不太喜欢db上下文将成为控制器成员的想法.
我真的更喜欢在数据访问层中保留db上下文，而不是将其传递到存储库类中.
是否可以在数据访问层中获取上下文?(据我所知，那里没有IServiceCollection，IApplicationBuilder，IServiceScopeFactory)

However, I'm not very fond of the idea that the db context will be a member at the controller.
I really prefer to get a hold of the db context in the data access layer instead of getting it passed into the repositories classes.
Is there a way to get the context inside the data access layer? (There is no IServiceCollection, IApplicationBuilder, IServiceScopeFactory there as far as I know)

推荐答案

我了解您要执行的操作.我确实做到了.关键是在使用IServiceCollection的DAL中创建一个静态类.然后在这里添加您的上下文，这是我的，并且可以正常工作我的前端甚至不了解实体框架，nethier可以访问我的业务层:

I Understand what you are trying to do. I have done exactly that. The key is to Create a static class in your DAL that uses the IServiceCollection. then in here you add your context here's mine and it works a treat My front end doesn't even know about entity framework, nethier does my business layer:

public static IServiceCollection RegisterRepositoryServices(this IServiceCollection services)
    {
        services.AddIdentity<ApplicationUser, IdentityRole<int>>(
            config => { config.User.RequireUniqueEmail = true;
                config.Cookies.ApplicationCookie.LoginPath = "/Account/Login";
                config.Cookies.ApplicationCookie.AuthenticationScheme = "Cookie";
                config.Cookies.ApplicationCookie.AutomaticAuthenticate = false;
                config.Cookies.ApplicationCookie.Events = new CookieAuthenticationEvents()
                {
                    OnRedirectToLogin = async ctx =>
                    {
                        if (ctx.Request.Path.StartsWithSegments("/visualjobs") && ctx.Response.StatusCode == 200)
                        {
                            ctx.Response.StatusCode = 401;
                        }
                        else
                        {
                            ctx.Response.Redirect(ctx.RedirectUri);
                        }
                        await Task.Yield();
                    }
                };
            }).AddEntityFrameworkStores<VisualJobsDbContext, int>()
          .AddDefaultTokenProviders();

        services.AddEntityFramework().AddDbContext<VisualJobsDbContext>();

        services.AddScoped<IRecruiterRepository, RecruiterRepository>();
        services.AddSingleton<IAccountRepository, AccountRepository>();

        return services;
    }

然后在服务层中，我还有另一个静态类.我的服务层引用了存储库层，我在这里注册了存储库服务(将存储库引导到服务层)，就像这样，然后我在UI中再次进行了同样的操作:

then in my service layer I have another static class. My service layer has a reference to the repository layer and I register the repository services here (bootstrapping the repository into the service layer), like so and then I do the same again in the UI:

服务层代码:

public static class ServiceCollectionExtensions
{
    public static IServiceCollection RegisterServices(this IServiceCollection services)
    {
        services.RegisterRepositoryServices();
        services.AddScoped<IRecruiterService, RecruiterService>();
        services.AddSingleton<IAccountService, AccountService>();

        return services;
    }
}

存储库层中的魔力:

public partial class VisualJobsDbContext : IdentityDbContext<ApplicationUser, IdentityRole<int>, int>
{
    private IConfigurationRoot _config;

    public VisualJobsDbContext() { }

    public VisualJobsDbContext(IConfigurationRoot config, DbContextOptions<VisualJobsDbContext> options) : base(options)
    {
        _config = config;
    }
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        base.OnConfiguring(optionsBuilder);

        optionsBuilder.UseSqlServer(@_config["ConnectionStrings:VisualJobsContextConnection"]);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {....

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