ASP NET Core 2无法找到包＆＃39; Projectname.Model＆＃39;

Question

在我的解决方案中，我有两个项目。其中一个是web项目，另一个是Model项目。您可以在下面看到我的解决方案结构：

现在，当我运行应用程序时，我收到以下错误：

  

InvalidOperationException：找不到包＆＃39; ContosoUniversity.Model＆＃39;

的编译库位置

这里是完整的堆栈跟踪：

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()

我使用ASP NET Core 2和VS17。

如果您需要，请输入我的ContosoUniversity.csproj文件：

<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>

我该怎么做才能解决这个问题？

Answer 1

为了使asp.net core 2.0项目成功找到外部程序集.NETStandard2.0，您需要覆盖内置的MetadataReferenceFeatureProvider。为此，我们需要添加以下类：

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);
            }
        }
    }
}

并且还要替换你的Startup＆＃34; services.AddMvc（）＆＃34;使用以下代码：

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());
    });

Answer 2

要解决此问题，您应该在Startup构造函数中注入IServiceProvider，如下所示：

 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();

    }

Answer 3

如果您的应用正在运行时中编译Razor代码，并且您使用的是.netcore2 +，则似乎需要将其添加到项目中：

<MvcRazorExcludeRefAssembliesFromPublish>false</MvcRazorExcludeRefAssembliesFromPublish>

这会在发布时复制refs文件夹-它很大-但似乎是必需的

Answer 4

经过多次尝试，我解决了这个问题。 您只需要更改.csproj并切换

<Project Sdk="Microsoft.NET.Sdk">

与

<Project Sdk="Microsoft.NET.Sdk.Razor">

我在csproj中添加了其他几行，但是我相信这是唯一需要的行。

Answer 5

您可能在发布没有参考程序集的应用程序。尝试设置

<CopyRefAssembliesToPublishDirectory>true</CopyRefAssembliesToPublishDirectory>

在您应用的项目文件中。

Answer 6

对我来说，我需要在发布配置文件中选择“在目的地删除其他文件”才能解决这个问题。我们开发团队的另一名成员最近从他们的机器上发布了可能已考虑在内的内容。

但是请注意您的项目 - 如果您在服务器上有本地没有的资产，它们将被删除（例如用户上传的内容）。