How to prevent EF4 from dynamically loading all assemblies

2018-07-02 08:36:31

We use ClickOnce with dynamic assembly loading. I recently added an EF4 model to a "Model" project within the solution.

The application must not use the app.config file for it's connection string, so I create the ObjectContext using an EntityConnection.

The application logic works perfectly, however, when you create an instance of the ObjectContext when the application is deployed using ClickOnce, EF4 tries to dynamically load all of the associated assemblies to find the metadata.

This forces clickonce to download every single assembly in the clickonce dll map!

Here is the stack trace when calling the ObjectContext ctor:

   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)

How can I prevent EF4 from doing this?

Thanks!

After following Craig's advice I am now able to create an instance of the ObjectContext without it trying to load all of the assemblies.

However, it now tries to load all of the assemblies when a query is run. Please see stack trace below:

   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)

I would appreciate any further assistance! Thanks.

Well I think that if the * is used, it should first check the current assembly. 99% of the time that would be correct. Loading every single assembly and then only checking the current assembly seems like a bug to me.

It should be optional for it to use reflection to attempt to load every single dll.

I am still having issues with this though. The model library which contains all the business logic for the company, is being used elsewhere (not the original ClickOnce application mentioned above). This library references crystal report's DLLs which now causes EF4 to throw a ReflectTypeLoadException because that machine does not have crystal installed.

And yes, this is without the * wildcard and with pre-generated views.

Is there REALLY no way to explicitly tell EF4 NOT TO LOAD ASSEMBLIES (it really doesn't need to)? Otherwise it looks like I am going to have to abandon EF4 completely.

您应该在您的EF连接字符串中指定正确的程序集，而不是使用*通配符。

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