c# – Roslyn – 从内存中组装创建MetadataReference

使用ASP.NET 5应用程序(Visual Studio 2015 CTP5)和Microsoft.CodeAnalysis.CSharp.

如果我尝试创建一个MetadataReference到一个程序集,该程序集是解决方案的一部分,将其作为对CSharpCompilation.Create的引用传递,我得到一个System.ArgumentException,“空路径名称不合法”.

// Throws exception
MetadataReference.CreateFromAssembly(typeof(this).Assembly);

// Doesn't throw exception
MetadataReference.CreateFromAssembly(typeof(Object).Assembly);

如果我检查程序集的Location属性,它是空的.我假设这与在ASP.NET 5中编译内存中应用程序的新方法有关,因此程序集不会存储在光盘上.

那么有没有办法将Roslyn的引用传递给没有Location属性的程序集,或者目前是不支持的?

编辑:
@JaredPar – @SLaks已经突出显示了它失败的确切位置,但这里是信息的完整堆栈跟踪.我之前在System.*程序集中创建了其他几个MetadataReferences,并且它们中没有任何问题.

System.ArgumentException
Empty path name is not legal.
C:\Development\Incubator\net.framework\src\Webfuel.Services.Host\ScriptHelper\ScriptHelper.cs
Line 86:  
Line 87:              // Compile the code
Line 88:              var compilation = CSharpCompilation.Create(
Line 89:                  assemblyName,Line 90:                  options: new CSharpCompilationOptions(outputKind: OutputKind.DynamicallyLinkedLibrary),at System.IO.FileStream.Init(String path,FileMode mode,FileAccess access,Int32 rights,Boolean useRights,FileShare share,Int32 bufferSize,FileOptions options,Win32Native.SECURITY_ATTRIBUTES secAttrs,String msgPath,Boolean bFromProxy,Boolean useLongPath,Boolean checkHost)
at System.IO.FileStream..ctor(String path,FileShare share) 
at System.IO.File.OpenRead(String path) 
at Microsoft.CodeAnalysis.InternalUtilities.FileStreamLightUp.OpenFileStream(String path) 
at Microsoft.CodeAnalysis.MetadataReference.CreateFromAssembly(Assembly assembly,MetadataReferenceProperties properties,DocumentationProvider documentation) 
at Microsoft.CodeAnalysis.MetadataReference.CreateFromAssembly(Assembly assembly) 
at Webfuel.Services.Host.ScriptHelper.CompileScriptImpl(String source) in C:\Development\Incubator\net.framework\src\Webfuel.Services.Host\ScriptHelper\ScriptHelper.cs:line 88 
at Webfuel.Services.Host.ScriptHelper.<>c__DisplayClass0.<CompileTemplate>b__3(String source) in C:\Development\Incubator\net.framework\src\Webfuel.Services.Host\ScriptHelper\ScriptHelper.cs:line 71 
at System.Collections.Concurrent.ConcurrentDictionary<TKey,TValue>.GetOrAdd(TKey key,Func<TKey,TValue> valueFactory) 
at Webfuel.Services.Host.ScriptHelper.CompileTemplate(String template) in C:\Development\Incubator\net.framework\src\Webfuel.Services.Host\ScriptHelper\ScriptHelper.cs:line 69 
at Webfuel.Services.Host.SandBoxContext.<ExecuteTemplateAsync>d__1.MoveNext() in C:\Development\Incubator\net.framework\src\Webfuel.Services.Host\SandBoxContext.cs:line 176 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter<TResult>.GetResult() 
at Webfuel.Services.Host.SandBoxHost.<ExecuteTemplateAsync>d__1.MoveNext() in C:\Development\Incubator\net.framework\src\Webfuel.Services.Host\SandBoxHost.cs:line 39 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter<TResult>.GetResult() 
at Webfuel.Services.SandBox.SandBoxService.<ExecuteTemplateAsync>d__1.MoveNext() in C:\Development\Incubator\net.framework\src\Webfuel.Services.SandBox\SandBoxService.cs:line 47 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter<TResult>.GetResult() 
at Webfuel.Services.Server.ServerService.<ProcessContentRequestAsync>d__1.MoveNext() in C:\Development\Incubator\net.framework\src\Webfuel.Services.Server\ServerService.cs:line 179 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter<TResult>.GetResult() 
at Webfuel.Services.Server.ServerService.<ProcessRequestAsync>d__1.MoveNext() in C:\Development\Incubator\net.framework\src\Webfuel.Services.Server\ServerService.cs:line 73 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter<TResult>.GetResult() 
at Webfuel.App.ServerMiddleware.<Invoke>d__1.MoveNext() in C:\Development\Incubator\net.framework\src\Webfuel.App\Startup.cs:line 89 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.GetResult() 
at Microsoft.AspNet.RequestContainer.ContainerMiddleware.<Invoke>d__1.MoveNext() 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.GetResult() 
at Microsoft.AspNet.Loader.IIS.KlrHttpApplication.<ProcessRequestAsyncImpl>d__1.MoveNext() 
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) 
at System.Runtime.CompilerServices.TaskAwaiter.GetResult() 
at Microsoft.AspNet.Loader.IIS.HttpApplicationBase.<InvokeProcessRequestAsyncImpl>d__1.MoveNext()

解决方法

已经有一段时间了,但我确实在github Roslyn存储库上得到了答案,所以如果有人发现这个问题,我会发布它:

ASP.NET 5有一个API.你可以做Razor做的https://github.com/aspnet/Mvc/blob/dev/src/Microsoft.AspNet.Mvc.Razor/Compilation/RoslynCompilationService.cs#L132

这回到了Asp.Net 5的Beta1左右,所以可能需要调整但原理仍然相同 – 遵循Asp.Net本身通过服务注入器将提供的IAssemblyLoadContextAccessor使用的API.

感谢David Fowler

更新:这个答案是针对ASP.NET 5 Beta1的. API发生了很大变化,在Core 1.0中,而不是使用IAssemblyLoadContextAccessor,您可以从静态成员访问AssemblyLoadContext:

System.Runtime.Loader.AssemblyLoadContext.Default

然后,您可以调用LoadFromStream从二进制映像加载程序集.这是我使用的代码的一个非常粗略的草图,其中一些不相关的部分被破解:

// Give the assembly a unique name
        var assemblyName = "Gen" + Guid.NewGuid().ToString().Replace("-","") + ".dll";

        // Build the Syntax tree
        var SyntaxTree = CSharpSyntaxTree.ParseText(source);

        // Compile the code
        var compilation = CSharpCompilation.Create(
            assemblyName,options: new CSharpCompilationOptions(outputKind: OutputKind.DynamicallyLinkedLibrary),SyntaxTrees: new List<SyntaxTree> { SyntaxTree },references: GetMetadataReferences());

        // Emit the image of this assembly 
        byte[] image = null;
        using (var ms = new MemoryStream())
        {
            var emitResult = compilation.Emit(ms);
            if (!emitResult.Success)
            {
                throw new InvalidOperationException();
            }
            image = ms.ToArray();
        }

        Assembly assembly = null;

        // NETCORE
        using (var stream = new MemoryStream(image))
            assembly = System.Runtime.Loader.AssemblyLoadContext.Default.LoadFromStream(stream);

这不应该按原样运行,而只是想一想主要步骤.

此外,仅从内存中的程序集生成元数据引用的问题不再存在,因为Core 1.0中不再存在这些引用,因此每个程序集都具有Location属性.因此,获取这些引用基本上与ASP.net 4中的过程相同:

MetadataReference.CreateFromFile(Assembly.Load(new AssemblyName(assemblyName)).Location);

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