ASP NET Core 2 Cannot find compilation library location for package 'Projectname.Model'

问题:

In my solution, I have two projects. One of them is web project and the other one is Model project. You can see my solution structure in below:

Now when I run application I get the following error:

InvalidOperationException: Cannot find compilation library location for package 'ContosoUniversity.Model'

And here is full stack trace :

An unhandled exception occurred while processing the request. InvalidOperationException: Cannot find compilation library location for package 'ContosoUniversity.Model' Microsoft.Extensions.DependencyModel.CompilationLibrary.ResolveReferencePaths(ICompilationAssemblyResolver resolver, List<string> assemblies) InvalidOperationException: Cannot find compilation library location for package 'ContosoUniversity.Model' Microsoft.Extensions.DependencyModel.CompilationLibrary.ResolveReferencePaths(ICompilationAssemblyResolver resolver, List<string> assemblies) Microsoft.Extensions.DependencyModel.CompilationLibrary.ResolveReferencePaths() Microsoft.AspNetCore.Mvc.ApplicationParts.AssemblyPart+<>c.<GetReferencePaths>b__8_0(CompilationLibrary library) System.Linq.Enumerable+SelectManySingleSelectorIterator.MoveNext() Microsoft.AspNetCore.Mvc.Razor.Compilation.MetadataReferenceFeatureProvider.PopulateFeature(IEnumerable<ApplicationPart> parts, MetadataReferenceFeature feature) Microsoft.AspNetCore.Mvc.ApplicationParts.ApplicationPartManager.PopulateFeature<TFeature>(TFeature feature) Microsoft.AspNetCore.Mvc.Razor.Internal.DefaultRazorReferenceManager.GetCompilationReferences() System.Threading.LazyInitializer.EnsureInitializedCore<T>(ref T target, ref bool initialized, ref object syncLock, Func<T> valueFactory) Microsoft.AspNetCore.Mvc.Razor.Internal.DefaultRazorReferenceManager.get_CompilationReferences() Microsoft.AspNetCore.Mvc.Razor.Internal.LazyMetadataReferenceFeature.get_References() Microsoft.CodeAnalysis.Razor.CompilationTagHelperFeature.GetDescriptors() Microsoft.AspNetCore.Razor.Language.DefaultRazorTagHelperBinderPhase.ExecuteCore(RazorCodeDocument codeDocument) Microsoft.AspNetCore.Razor.Language.RazorEnginePhaseBase.Execute(RazorCodeDocument codeDocument) Microsoft.AspNetCore.Razor.Language.DefaultRazorEngine.Process(RazorCodeDocument document) Microsoft.AspNetCore.Razor.Language.RazorTemplateEngine.GenerateCode(RazorCodeDocument codeDocument) Microsoft.AspNetCore.Mvc.Razor.Internal.RazorViewCompiler.CompileAndEmit(string relativePath) Microsoft.AspNetCore.Mvc.Razor.Internal.RazorViewCompiler.CreateCacheEntry(string normalizedPath)  System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) System.Runtime.CompilerServices.TaskAwaiter.GetResult() Microsoft.AspNetCore.Mvc.Razor.Internal.DefaultRazorPageFactoryProvider.CreateFactory(string relativePath) Microsoft.AspNetCore.Mvc.Razor.RazorViewEngine.CreateCacheResult(HashSet<IChangeToken> expirationTokens, string relativePath, bool isMainPage) Microsoft.AspNetCore.Mvc.Razor.RazorViewEngine.OnCacheMiss(ViewLocationExpanderContext expanderContext, ViewLocationCacheKey cacheKey) Microsoft.AspNetCore.Mvc.Razor.RazorViewEngine.LocatePageFromViewLocations(ActionContext actionContext, string pageName, bool isMainPage) Microsoft.AspNetCore.Mvc.Razor.RazorViewEngine.FindView(ActionContext context, string viewName, bool isMainPage) Microsoft.AspNetCore.Mvc.ViewEngines.CompositeViewEngine.FindView(ActionContext context, string viewName, bool isMainPage) Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.ViewResultExecutor.FindView(ActionContext actionContext, ViewResult viewResult) Microsoft.AspNetCore.Mvc.ViewResult+<ExecuteResultAsync>d__26.MoveNext() System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeResultAsync>d__19.MoveNext() System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeNextResultFilterAsync>d__24.MoveNext() System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResultExecutedContext context) Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted) Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeNextResourceFilter>d__22.MoveNext() System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context) Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted) Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeFilterPipelineAsync>d__17.MoveNext() System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeAsync>d__15.MoveNext() System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) Microsoft.AspNetCore.Builder.RouterMiddleware+<Invoke>d__4.MoveNext() System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware+<Invoke>d__7.MoveNext() 

I use ASP NET Core 2 and VS17.

Here is my ContosoUniversity.csproj file if you need it:

<Project Sdk="Microsoft.NET.Sdk.Web">  <PropertyGroup>   <TargetFramework>netcoreapp2.0</TargetFramework> </PropertyGroup>  <ItemGroup>   <PackageReference Include="Microsoft.AspNetCore.All" Version="2.0.0" />   <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.0.0" /> </ItemGroup>  <ItemGroup>   <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0" /> </ItemGroup>  <ItemGroup>   <Reference Include="ContosoUniversity.Model">     <HintPath>..\ContosoUniversity.Model\bin\Debug\netcoreapp2.0\ContosoUniversity.Model.dll</HintPath>   </Reference> </ItemGroup>  </Project> 

What should I do to solve this problem?

回答1:

For resolve this problem you should inject IServiceProvider in Startup constructor like this:

 public Startup(IConfiguration configuration, IHostingEnvironment env, IServiceProvider serviceProvider)     {         Configuration = configuration;          var builder = new ConfigurationBuilder()         .SetBasePath(env.ContentRootPath)         .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)         .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);          var mvcBuilder = serviceProvider.GetService<IMvcBuilder>();         new MvcConfiguration().ConfigureMvc(mvcBuilder);          Configuration = builder.Build();      } 

回答2:

In order asp.net core 2.0 project had successfully found external assemblies .NETStandard2.0, you need to override a built-in MetadataReferenceFeatureProvider. For this we need to add the following class:

using System; using System.Collections.Generic; using System.IO; using System.Linq; using System.Reflection.PortableExecutable; using Microsoft.AspNetCore.Mvc.ApplicationParts; using Microsoft.CodeAnalysis; using Microsoft.Extensions.DependencyModel;  namespace Microsoft.AspNetCore.Mvc.Razor.Compilation {     /// <summary>Провайдер нужен для компенсации бага компиляции представлений при подключении сборок .NetStandart2.0</summary>     public class ReferencesMetadataReferenceFeatureProvider : IApplicationFeatureProvider<MetadataReferenceFeature>     {         public void PopulateFeature(IEnumerable<ApplicationPart> parts, MetadataReferenceFeature feature)         {             var libraryPaths = new HashSet<string>(StringComparer.OrdinalIgnoreCase);             foreach (var assemblyPart in parts.OfType<AssemblyPart>())             {                 var dependencyContext = DependencyContext.Load(assemblyPart.Assembly);                 if (dependencyContext != null)                 {                     foreach (var library in dependencyContext.CompileLibraries)                     {                         if (string.Equals("reference", library.Type, StringComparison.OrdinalIgnoreCase))                         {                             foreach (var libraryAssembly in library.Assemblies)                             {                                 libraryPaths.Add(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, libraryAssembly));                             }                         }                         else                         {                             foreach (var path in library.ResolveReferencePaths())                             {                                 libraryPaths.Add(path);                             }                         }                     }                 }                 else                 {                     libraryPaths.Add(assemblyPart.Assembly.Location);                 }             }              foreach (var path in libraryPaths)             {                 feature.MetadataReferences.Add(CreateMetadataReference(path));             }         }          private static MetadataReference CreateMetadataReference(string path)         {             using (var stream = File.OpenRead(path))             {                 var moduleMetadata = ModuleMetadata.CreateFromStream(stream, PEStreamOptions.PrefetchMetadata);                 var assemblyMetadata = AssemblyMetadata.Create(moduleMetadata);                  return assemblyMetadata.GetReference(filePath: path);             }         }     } } 

And also replace in your Startup "services.AddMvc()" with the following code:

services.AddMvc() // Следующий патч нужен для компенсации бага компиляции представлений при подключении сборок .NetStandart2.0     .ConfigureApplicationPartManager(manager =>     {         manager.FeatureProviders.Remove(manager.FeatureProviders.First(f => f is MetadataReferenceFeatureProvider));         manager.FeatureProviders.Add(new ReferencesMetadataReferenceFeatureProvider());     }); 

文章来源: ASP NET Core 2 Cannot find compilation library location for package 'Projectname.Model'