NopCommerce 4.20 依赖注入插件开发错误

Question

我有一个NopCommerce插件开发，名称为dBContext BookAppointmentDBContext和Dependency Registrar DependencyRegistrar请参阅下面的代码片段。

public class DependencyRegistrar : IDependencyRegistrar
{
    private const string CONTEXT_NAME ="nop_object_context_bookappointment";
    public  void Register(ContainerBuilder builder, ITypeFinder typeFinder, NopConfig config)
    {
        builder.RegisterType<BookAppointmentService>().As<IBookAppointmentService>().InstancePerLifetimeScope();
        //data context
        builder.RegisterPluginDataContext<BookAppointmentDBContext>(CONTEXT_NAME);
        //override required repository with our custom context
        builder.RegisterType<EfRepository<CarInspectionModel>>()
            .As<IRepository<CarInspectionModel>>()
            .WithParameter(ResolvedParameter.ForNamed<IDbContext>(CONTEXT_NAME))
            .InstancePerLifetimeScope();
    }
    public int Order => 1;
}

和下面的BookAppointmentDBContext类

public class BookAppointmentDBContext : DbContext, IDbContext
{
    #region Ctor
    public BookAppointmentDBContext(DbContextOptions<BookAppointmentDBContext> options) : base(options)
    {
    }
  /*the other implementation of IDbContext as found in http://docs.nopcommerce.com/display/en/Plugin+with+data+access*/
}

另外，我有一个 BasePluglin 类

public class BookAppointmentPlugin : BasePlugin
{
    private IWebHelper _webHelper;
    private readonly BookAppointmentDBContext _context;
    public BookAppointmentPlugin(IWebHelper webHelper, BookAppointmentDBContext context)
    {
        _webHelper = webHelper;
        _context = context;
    }
    public override void Install()
    {
        _context.Install();
        base.Install();
    }
    public override void Uninstall()
    {
        _context.Uninstall();
        base.Uninstall();
    }
}

我一直有这个错误： ComponentNotRegisteredException: The requested service 'Microsoft.EntityFrameworkCore.DbContextOption 1[[Nop.Plugin.Misc.BookAppointment.Models.BookAppointmentDBContext, Nop.Plugin.Misc.BookAppointment, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]] has not been registered. To avoid this exception, either register a component to provide the service, check for service registration using IsRegistered(), or use the ResolveOptional() method to resolve an optional dependency.

我已经注册BookAppointmentDBContext但错误状态并非如此。知道我做错了什么吗？

Answer 1

此问题是缺少注册DbContextOption，这是初始化目标数据库上下文所需的构造函数的一部分。

在内部，这就是RegisterPluginDataContext所做的。

/// <summary>
/// Represents extensions of Autofac ContainerBuilder
/// </summary>
public static class ContainerBuilderExtensions
{
    /// <summary>
    /// Register data context for a plugin
    /// </summary>
    /// <typeparam name="TContext">DB Context type</typeparam>
    /// <param name="builder">Builder</param>
    /// <param name="contextName">Context name</param>
    public static void RegisterPluginDataContext<TContext>(this ContainerBuilder builder, string contextName) where TContext : DbContext, IDbContext
    {
        //register named context
        builder.Register(context => (IDbContext)Activator.CreateInstance(typeof(TContext), new[] { context.Resolve<DbContextOptions<TContext>>() }))
            .Named<IDbContext>(contextName).InstancePerLifetimeScope();
    }
}

源

请注意，它在激活上下文时尝试解决DbContextOptions<TContext>。

您需要构建数据库上下文选项并将其提供给容器，以便在解析时可以将其注入到上下文中。

private const string CONTEXT_NAME ="nop_object_context_bookappointment";
public  void Register(ContainerBuilder builder, ITypeFinder typeFinder, NopConfig config) {
    //...code removed for brevity
    var optionsBuilder = new DbContextOptionsBuilder<BookAppointmentDBContext>();
    optionsBuilder.UseSqlServer(connectionStringHere);
    DbContextOptions<BookAppointmentDBContext> options = optionsBuilder.Options;
    builder.RegisterInstance<DbContextOptions<BookAppointmentDBContext>>(options); 
    //data context
    builder.RegisterPluginDataContext<BookAppointmentDBContext>(CONTEXT_NAME);
    //...code removed for brevity
}

参考 配置数据库上下文