如何防止 EF4 动态加载所有程序集

Question

我们使用带有动态程序集加载的 ClickOnce。我最近在解决方案中的“模型”项目中添加了一个 EF4 模型。

应用程序不得使用 app.config 文件作为其连接字符串，因此我使用 EntityConnection 创建 ObjectContext。

应用程序逻辑运行良好，但是，当您在使用 ClickOnce 部署应用程序时创建 ObjectContext 的实例时，EF4 会尝试动态加载所有关联的程序集以查找元数据。

这会强制 clickonce 下载 clickonce dll 映射中的每个程序集！

这是调用 ObjectContext ctor 时的堆栈跟踪：

   at System.AppDomain.OnAssemblyResolveEvent(RuntimeAssembly assembly, String assemblyFullName)
   at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.Assembly.Load(AssemblyName assemblyRef)
   at System.Data.Metadata.Edm.MetadataAssemblyHelper.SafeLoadReferencedAssembly(AssemblyName assemblyName)
   at System.Data.Metadata.Edm.MetadataAssemblyHelper.<GetNonSystemReferencedAssemblies>d__0.MoveNext()
   at System.Data.Metadata.Edm.DefaultAssemblyResolver.GetAllDiscoverableAssemblies()
   at System.Data.Metadata.Edm.DefaultAssemblyResolver.GetWildcardAssemblies()
   at System.Data.Metadata.Edm.MetadataArtifactLoaderCompositeResource.LoadResources(String assemblyName, String resourceName, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
   at System.Data.Metadata.Edm.MetadataArtifactLoaderCompositeResource.CreateResourceLoader(String path, ExtensionCheck extensionCheck, String validExtension, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
   at System.Data.Metadata.Edm.MetadataArtifactLoader.Create(String path, ExtensionCheck extensionCheck, String validExtension, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
   at System.Data.Metadata.Edm.MetadataCache.SplitPaths(String paths)
   at System.Data.Common.Utils.Memoizer`2.<>c__DisplayClass2.<Evaluate>b__0()
   at System.Data.Common.Utils.Memoizer`2.Result.GetValue()
   at System.Data.Common.Utils.Memoizer`2.Evaluate(TArg arg)
   at System.Data.EntityClient.EntityConnection.GetMetadataWorkspace(Boolean initializeAllCollections)
   at System.Data.Objects.ObjectContext.RetrieveMetadataWorkspaceFromConnection()
   at System.Data.Objects.ObjectContext..ctor(EntityConnection connection, Boolean isConnectionConstructor)

如何防止 EF4 这样做？

谢谢！

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遵循 Craig 的建议后，我现在可以创建 ObjectContext 的实例，而无需尝试加载所有程序集。

但是，它现在会在运行查询时尝试加载所有程序集。请参阅下面的堆栈跟踪：

   at System.AppDomain.OnAssemblyResolveEvent(RuntimeAssembly assembly, String assemblyFullName)
   at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection, Boolean suppressSecurityChecks)
   at System.Reflection.Assembly.Load(AssemblyName assemblyRef)
   at System.Data.Metadata.Edm.MetadataAssemblyHelper.SafeLoadReferencedAssembly(AssemblyName assemblyName)
   at System.Data.Metadata.Edm.MetadataAssemblyHelper.<GetNonSystemReferencedAssemblies>d__0.MoveNext()
   at System.Data.Metadata.Edm.ObjectItemCollection.ImplicitLoadViewsFromAllReferencedAssemblies(Assembly assembly)
   at System.Data.Mapping.StorageMappingItemCollection.ViewDictionary.SerializedCollectViewsFromReferencedAssemblies(MetadataWorkspace workspace, Dictionary`2 extentMappingViews)
   at System.Data.Mapping.StorageMappingItemCollection.ViewDictionary.SerializedGetGeneratedViews(EntityContainer container)
   at System.Data.Common.Utils.Memoizer`2.<>c__DisplayClass2.<Evaluate>b__0()
   at System.Data.Common.Utils.Memoizer`2.Result.GetValue()
   at System.Data.Common.Utils.Memoizer`2.Evaluate(TArg arg)
   at System.Data.Mapping.StorageMappingItemCollection.ViewDictionary.GetGeneratedView(EntitySetBase extent, MetadataWorkspace workspace, StorageMappingItemCollection storageMappingItemCollection)
   at System.Data.Metadata.Edm.MetadataWorkspace.GetGeneratedView(EntitySetBase extent)
   at System.Data.Query.PlanCompiler.PreProcessor.ExpandView(Node node, ScanTableOp scanTableOp, IsOfOp& typeFilter)
   at System.Data.Query.PlanCompiler.PreProcessor.ProcessScanTable(Node scanTableNode, ScanTableOp scanTableOp, IsOfOp& typeFilter)
   at System.Data.Query.PlanCompiler.PreProcessor.Visit(ScanTableOp op, Node n)
   at System.Data.Query.InternalTrees.ScanTableOp.Accept[TResultType](BasicOpVisitorOfT`1 v, Node n)
   at System.Data.Query.InternalTrees.BasicOpVisitorOfT`1.VisitNode(Node n)
   at System.Data.Query.PlanCompiler.SubqueryTrackingVisitor.VisitChildren(Node n)
   at System.Data.Query.PlanCompiler.SubqueryTrackingVisitor.VisitRelOpDefault(RelOp op, Node n)
   at System.Data.Query.PlanCompiler.PreProcessor.Visit(ProjectOp op, Node n)
   at System.Data.Query.InternalTrees.ProjectOp.Accept[TResultType](BasicOpVisitorOfT`1 v, Node n)
   at System.Data.Query.InternalTrees.BasicOpVisitorOfT`1.VisitNode(Node n)
   at System.Data.Query.PlanCompiler.SubqueryTrackingVisitor.VisitChildren(Node n)
   at System.Data.Query.InternalTrees.BasicOpVisitorOfNode.VisitDefault(Node n)
   at System.Data.Query.InternalTrees.BasicOpVisitorOfNode.VisitPhysicalOpDefault(PhysicalOp op, Node n)
   at System.Data.Query.InternalTrees.BasicOpVisitorOfT`1.Visit(PhysicalProjectOp op, Node n)
   at System.Data.Query.InternalTrees.PhysicalProjectOp.Accept[TResultType](BasicOpVisitorOfT`1 v, Node n)
   at System.Data.Query.InternalTrees.BasicOpVisitorOfT`1.VisitNode(Node n)
   at System.Data.Query.PlanCompiler.PreProcessor.Process()
   at System.Data.Query.PlanCompiler.PreProcessor.Process(PlanCompiler planCompilerState, StructuredTypeInfo& typeInfo)
   at System.Data.Query.PlanCompiler.PlanCompiler.Compile(List`1& providerCommands, ColumnMap& resultColumnMap, Int32& columnCount, Set`1& entitySets)
   at System.Data.EntityClient.EntityCommandDefinition..ctor(DbProviderFactory storeProviderFactory, DbCommandTree commandTree)
   at System.Data.EntityClient.EntityProviderServices.CreateCommandDefinition(DbProviderFactory storeProviderFactory, DbCommandTree commandTree)
   at System.Data.EntityClient.EntityProviderServices.CreateDbCommandDefinition(DbProviderManifest providerManifest, DbCommandTree commandTree)
   at System.Data.Common.DbProviderServices.CreateCommandDefinition(DbCommandTree commandTree)
   at System.Data.Objects.Internal.ObjectQueryExecutionPlan.Prepare(ObjectContext context, DbQueryCommandTree tree, Type elementType, MergeOption mergeOption, Span span, ReadOnlyCollection`1 compiledQueryParameters)
   at System.Data.Objects.EntitySqlQueryState.GetExecutionPlan(Nullable`1 forMergeOption)
   at System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
   at System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)

如果有任何进一步的帮助，我将不胜感激！ 谢谢。

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好吧，我认为如果使用*，它应该首先检查当前程序集。 99% 的时间都是正确的。加载每个程序集然后只检查当前程序集对我来说似乎是一个错误。

使用反射来尝试加载每个 dll 应该是可选的。

我仍然有这个问题。包含公司所有业务逻辑的模型库正在其他地方使用（不是上面提到的原始 ClickOnce 应用程序）。该库引用了水晶报告的 DLL，这会导致 EF4 抛出 ReflectTypeLoadException，因为该机器没有安装水晶。

是的，这是没有 * 通配符和预先生成的视图。

真的没有办法明确告诉 EF4 不要加载程序集（它真的不需要）吗？否则看起来我将不得不完全放弃 EF4。

Answer 1

您应该使用specify the correct assembly in your EF connection string 而不是使用* 通配符。