[英]AutoFac DbContext issue - cannot be used while the model is creating
我在使用AutoFac和IoC時遇到了一些問題。 我們有一個有效的應用程序,但是我從頭開始使用這個應用程序並且無法看到兩者之間的差異。
我正在使用一個簡單的AJAX頁面測試它,該頁面通過ServiceStack API調用服務層。 當使用MockRepositories時,這很好用,所以我知道事情的一面是有效的。
但是當我用使用Entity Framework的模擬替換模擬時,盡管所有注冊看起來都是正確且有效的,但我得到錯誤“在創建模型時不能使用上下文”。
我在下面包含了我的代碼:
public class SomeObject
{
public int Id { get; set; }
}
public class IoCExampleContext : DbContext, IIoCExampleContext
{
public IDbSet<SomeObject> SomeObjects { get; set; }
static IoCExampleContext()
{
Database.SetInitializer(new IoCExampleDatabaseInitilizer());
}
public IoCExampleContext(string connectionStringName)
: base(connectionStringName)
{
Configuration.ProxyCreationEnabled = false;
}
public IoCExampleContext()
: this("name=IoCExample")
{}
public string ConnectionString
{
get { return Database.Connection.ConnectionString; }
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
BuildModels(modelBuilder);
}
private void BuildModels(DbModelBuilder builder)
{
var typeToUse = typeof(SomeObjectModelBuilder);
var namespaceToUse = typeToUse.Namespace;
var toReg = Assembly
.GetAssembly(typeToUse)
.GetTypes()
.Where(type => type.Namespace != null && type.Namespace.StartsWith(namespaceToUse))
.Where(type => type.BaseType.IsGenericType && type.BaseType.GetGenericTypeDefinition() == typeof(EntityTypeConfiguration<>));
foreach (object configurationInstance in toReg.Select(Activator.CreateInstance))
{
builder.Configurations.Add((dynamic)configurationInstance);
}
}
}
public class IoCExampleDatabaseInitilizer : CreateDatabaseIfNotExists<IoCExampleContext>
{
protected override void Seed(IoCExampleContext context)
{
}
}
public interface IRepository<TEntity> where TEntity : class
{
IQueryable<TEntity> GetQuery();
IEnumerable<TEntity> GetAll();
IEnumerable<TEntity> Where(Expression<Func<TEntity, bool>> predicate);
// ...Various "standard" CRUD calls
}
public class GenericRepository<TEntity> : IRepository<TEntity> where TEntity : class
{
protected DbContext _context;
private readonly DbSet<TEntity> _dbSet;
public GenericRepository(DbContext context)
{
_context = context;
_dbSet = _context.Set<TEntity>();
}
public IQueryable<TEntity> GetQuery()
{
return _dbSet;
}
public IEnumerable<TEntity> GetAll()
{
return GetQuery().AsEnumerable();
}
public IEnumerable<TEntity> Where(Expression<Func<TEntity, bool>> predicate)
{
return GetQuery().Where(predicate);
}
// ...Various "standard" CRUD calls
public void Dispose()
{
OnDispose(true);
}
protected void OnDispose(bool disposing)
{
if (disposing)
{
if (_context != null)
{
_context.Dispose();
_context = null;
}
}
}
}
public class DependencyBootstrapper
{
private ContainerBuilder _builder;
public IContainer Start()
{
_builder = new ContainerBuilder();
_builder.RegisterFilterProvider();
RegisterControllers();
return _builder.Build();
}
private void RegisterControllers()
{
RegisterAssembly(Assembly.GetExecutingAssembly());
_builder.RegisterModelBinderProvider();
RegisterPerLifetimeConnections();
RegisterRepositories();
RegisterServices();
}
private void RegisterAssembly(Assembly assembly)
{
_builder.RegisterModelBinders(assembly);
_builder.RegisterControllers(assembly);
}
private void RegisterRepositories()
{
_builder.RegisterGeneric(typeof(GenericRepository<>)).As(typeof(IRepository<>));
_builder.RegisterType<GenericRepository<SomeObject>>().As<IRepository<SomeObject>>();
//... More registrations
}
private void RegisterServices()
{
_builder.RegisterType<SomeObjectService>().As<ISomeObjectService>();
//... More registrations
}
private void RegisterPerLifetimeConnections()
{
const string connectionStringName = "IoCExample";
_builder.RegisterType<IoCExampleContext>()
.As<DbContext>()
.WithParameter("connectionStringName", connectionStringName)
.InstancePerLifetimeScope();
_builder.Register(c => new HttpContextWrapper(HttpContext.Current))
.As<HttpContextBase>();
}
}
我不知道它是否相關但由於我們無法訪問global.asax方法,我們通過PreApplicationStartMethod.OnPreApplicationStart
調用引導程序(據我所知,它與Application_Start幾乎相同) 。
有點令人擔憂的是,當我在連接字符串上啟用多個活動結果集時,它會起作用 - 這會告訴我我正在錯誤地注冊DbContext並且它跨越多個上下文。
誰能發現我哪里出錯?
連接字符串是個問題。 確保您已在web / app.comfig中正確設置。
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