当我尝试检索包含在动态加载的 DLL 中找到其类型的实体列表的文档时，我收到一个 JSONSerialization 异常，该异常表明它无法在动态加载的 DLL 中找到该类型。 DLL:无法加载程序集“Sandbox_One”
我正在使用 RavenDB(版本 2681)来存储使用 Roslyn 创建的实体，尽管我认为这不是问题。每个实体都继承一个非动态接口(interface)IEntity。 Raven session 正在 .NET MVC 4 Action 的任一侧创建(根据 Raven example )，我能够将动态实体保存到 IEntity 列表中。
当我尝试从文档中加载实体列表时，出现序列化错误。目前，我只有单个实体类型(客户)的单个实例(蓝眼睛)。
观察结果
- 在数据库中，实体看起来与我期望的一模一样:
{
"Entities": [
{
"$type": "Prometheus.Dynamic.Sandbox_One.Customer, Sandbox_One",
"Name": "Customer",
"Eye_colour": "Blue",
"Age": 9.0,
"Id": "b0937393-b1bf-4bcb-97d7-1aea7a96e881"
}
]
}
At the point of Loading the entity, I check the
AppDomain.CurrentDomainfor the loaded assemblies andPrometheus.Dynamic.Sandbox_Onewith theCustomertype is there.The
Realmobject has a reference to the dynamically loaded Assembly and I am able to reflect types from it like so:var customer = Activator.CreateInstance(realm.Assembly.GetTypes().First());The Assembly is loaded inside the MVC action, after the RavenDB session was started. Would that make a difference? I imagine not as I expect the JSON.net serializer is looking in the
AppDomain.
Code and Exception
Full stack trace of the Exception:
[JsonSerializationException: Could not load assembly 'Sandbox_One'.] Raven.Imports.Newtonsoft.Json.Serialization.DefaultSerializationBinder.GetTypeFromTypeNameKey(TypeNameKey typeNameKey) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\DefaultSerializationBinder.cs:69 Raven.Imports.Newtonsoft.Json.Utilities.ThreadSafeStore`2.AddValue(TKey key) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Utilities\ThreadSafeStore.cs:62 Raven.Imports.Newtonsoft.Json.Serialization.DefaultSerializationBinder.BindToType(String assemblyName, String typeName) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\DefaultSerializationBinder.cs:119 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadSpecialProperties(JsonReader reader, Type& objectType, JsonContract& contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue, Object& newValue, String& id) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:473 [JsonSerializationException: Error resolving type specified in JSON 'Prometheus.Dynamic.Sandbox_One.Customer, Sandbox_One'. Path 'Entities[0].$type'.] Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadSpecialProperties(JsonReader reader, Type& objectType, JsonContract& contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue, Object& newValue, String& id) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:526 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:344 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:238 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateList(IWrappedCollection wrappedList, JsonReader reader, JsonArrayContract contract, JsonProperty containerProperty, String id) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:1132 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateList(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue, String id) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:572 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:240 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.SetPropertyValue(JsonProperty property, JsonConverter propertyConverter, JsonContainerContract containerContract, JsonProperty containerProperty, JsonReader reader, Object target) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:692 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:1593 [JsonSerializationException: Could not read value for property: Entities] Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.PopulateObject(Object newObject, JsonReader reader, JsonObjectContract contract, JsonProperty member, String id) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:1602 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:368 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:238 Raven.Imports.Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalReader.cs:164 Raven.Imports.Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType) in c:\Builds\RavenDB-Stable\Imports\Newtonsoft.Json\Src\Newtonsoft.Json\JsonSerializer.cs:565 Raven.Client.Document.InMemoryDocumentSessionOperations.ConvertToEntity(Type entityType, String id, RavenJObject documentFound, RavenJObject metadata) in c:\Builds\RavenDB-Stable\Raven.Client.Lightweight\Document\InMemoryDocumentSessionOperations.cs:457 Raven.Client.Document.InMemoryDocumentSessionOperations.TrackEntity(Type entityType, String key, RavenJObject document, RavenJObject metadata, Boolean noTracking) in c:\Builds\RavenDB-Stable\Raven.Client.Lightweight\Document\InMemoryDocumentSessionOperations.cs:404 Raven.Client.Document.InMemoryDocumentSessionOperations.TrackEntity(Type entityType, JsonDocument documentFound) in c:\Builds\RavenDB-Stable\Raven.Client.Lightweight\Document\InMemoryDocumentSessionOperations.cs:388 Raven.Client.Document.InMemoryDocumentSessionOperations.TrackEntity(JsonDocument documentFound) in c:\Builds\RavenDB-Stable\Raven.Client.Lightweight\Document\InMemoryDocumentSessionOperations.cs:343 Raven.Client.Document.SessionOperations.LoadOperation.Complete() in c:\Builds\RavenDB-Stable\Raven.Client.Lightweight\Document\SessionOperations\LoadOperation.cs:61 Raven.Client.Document.DocumentSession.Load(String id) in c:\Builds\RavenDB-Stable\Raven.Client.Lightweight\Document\DocumentSession.cs:230 Prometheus.Core.DomainServices.DataManager.GetDataForRealm(IDocumentSession session, Realm realm) in c:\TeamProjectsCloud\Prometheus\Prometheus.Core\DomainServices\DataManager.cs:48 Prometheus.Portal.Controllers.DataController.Index(String entityName) in c:\TeamProjectsCloud\Prometheus\Prometheus.Portal\Controllers\DataController.cs:23 lambda_method(Closure , ControllerBase , Object[] ) +192 System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +274 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +39 System.Web.Mvc.Async.c__DisplayClass39.b__33() +120 System.Web.Mvc.Async.c__DisplayClass4f.b__49() +452 System.Web.Mvc.Async.c__DisplayClass37.b__36(IAsyncResult asyncResult) +15 System.Web.Mvc.Async.c__DisplayClass2a.b__20() +33 System.Web.Mvc.Async.c__DisplayClass25.b__22(IAsyncResult asyncResult) +240 System.Web.Mvc.c__DisplayClass1d.b__18(IAsyncResult asyncResult) +28 System.Web.Mvc.Async.c__DisplayClass4.b__3(IAsyncResult ar) +15 System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +53 System.Web.Mvc.Async.c__DisplayClass4.b__3(IAsyncResult ar) +15 System.Web.Mvc.c__DisplayClass8.b__3(IAsyncResult asyncResult) +42 System.Web.Mvc.Async.c__DisplayClass4.b__3(IAsyncResult ar) +15 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +606 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +288
The controller (I've bolded the call where the Entities are loaded):
NB RavenSession is inherited from a base controller exactly as in the MVC site example
public ActionResult Index(string entityName)
{
var viewModel = new DataViewModel();
var realm = realmManager.GetRealm(RavenSession, viewModel.SelectedRealm);
viewModel.Entities = realmManager.GetEntities(realm);
viewModel.CurrentEntity = viewModel.Entities.SingleOrDefault(x => x.Name == entityName);
viewModel.Data = dataManager.GetDataForRealm(RavenSession, realm); // Call to loading method
return View(viewModel);
}
抛出异常的 Load 调用:
public List<IEntity> GetDataForRealm(IDocumentSession session, Realm realm)
{
var realmData = session.Load<RealmData>(realm.RealmDataId); // Exception thrown
return realmData.Entities;
}
领域数据类:
public class RealmData
{
public RealmData()
{
Entities = new List<IEntity>();
}
public List<IEntity> Entities { get; set; }
}
预先感谢您的帮助!
最佳答案
我的解决方案是在应用程序域上实现 AssemblyResolve 事件处理程序。
GetDataForRealm 方法变为:
public List<IEntity> GetDataForRealm(IDocumentSession session, Realm realm)
{
AppDomain.CurrentDomain.AssemblyResolve += (s, a) => MyResolveEventHandler(s, a, realm.Assembly);
var realmData = session.Load<RealmData>(realm.RealmDataId);
return realmData.Entities;
}
事件处理程序如下所示:
private Assembly MyResolveEventHandler(object sender, ResolveEventArgs args, Assembly assembly)
{
if (assembly.GetName().Name == args.Name)
{
return assembly;
}
return null;
}
我认为正在发生的事情:
当 JSON.Net 反序列化器反射(reflect)动态类型时，它无法在 AppDomain.CurrentDomain 中找到程序集。当AppDomain无法按名称找到程序集时，将调用该处理程序。我的程序集位于 AppDomain 中(因为我使用了 Assembly.Load)，但找不到它。
注意:
我使用额外的参数扩展了 MyResolveEventHandler，因为我已经有了所需的程序集。如果内存中没有该程序集(但知道它在哪里)，则可以将其加载到 MyResovleEventHandler 中。
更新
您可能会发现稍后将数据分配给这些结果对象时遇到问题。这是因为通过 AppDomain 传递实体并不意味着它会更改对象的域。相反，它只是提供一个引用。相反，我发现使用在成员中具有动态程序集的自定义 JSON 转换器，让 RavenDB 首先在正确的(临时)域中创建对象会更容易。 See that solution here .
关于c# - Raven DB JsonSerializationException 无法加载程序集，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18878603/