c# - 迁移未开始 - Autofac 抛出异常

Question

我创建了一个抑制依赖关系的模块，该依赖关系又抑制了 Orchard.Users.Services.MembershipService

当我尝试启用该模块时，orchard 崩溃并出现异常:

Autofac.Core.DependencyResolutionException: An exception was thrown while invoking the constructor 'Void .ctor(...)' on type 'MembershipService'. 

有一个内部异常(exception)

System.Data.SqlClient.SqlException: Invalid object name 'MyModule_MyModel'

当然，该表不会退出，但应该按照 Migrations.cs 的定义创建

using System;
using Orchard.Data;
using Orchard.Data.Migration;
using MyModule.Models;

namespace MyModule
{
    public class Migrations : DataMigrationImpl
    {
        private readonly IRepository<SettingsRecord> _repository;

        public Migrations(IRepository<SettingsRecord> repository)
        {
            _repository = repository;
        }

        public int Create()
        {
            SchemaBuilder.CreateTable("SettingsRecord", table => table
                    .Column<int>("Id", column => column.PrimaryKey().Identity())
                    .Column<string>("DefaultDomain")
                );

            return 1;
        }
    }
}

此迁移未开始的原因可能是什么？

更新:

public MembershipService(
        IRepository<SettingsRecord> settingsRepository,
        IRepository<DomainRecord> domainsRepository,
        IOrchardServices orchardServices,
        IMessageManager messageManager,
        IEnumerable<IUserEventHandler> userEventHandlers,
        IClock clock,
        IEncryptionService encryptionService
        )
    {
        _settingsRepository = settingsRepository;
        _domainsRepository = domainsRepository;
        _orchardServices = orchardServices;
        _messageManager = messageManager;
        _userEventHandlers = userEventHandlers;
        _encryptionService = encryptionService;
        Logger = NullLogger.Instance;
        T = NullLocalizer.Instance;

        _defaultDomain = _settingsRepository.Table.FirstOrDefault().DefaultDomain;

        _baseMembershipService = new Orchard.Users.Services.MembershipService(orchardServices, messageManager, userEventHandlers, clock, encryptionService);
    }

Answer 1

这一行是您问题的根源:

_defaultDomain = _settingsRepository.Table.FirstOrDefault().DefaultDomain;

不是在 ctor 中设置这个值，而是将它包装在一个属性中(并添加 null 检查)。

除了简单的赋值外，避免在 ctor 中放入任何逻辑。那里发生的任何错误很可能会炸毁您的网站。