VS2017 MSBuildWorkspace無法使用轉換后的ASP.Net Core Web應用程序打開解決方案

Question

我已經使用Microsoft.CodeAnalysis軟件包設置了一些解決方案健全性測試，一切順利，我安裝了VS2017並轉換了我的ASP.Net Core Web應用程序。 由於csproj文件簡化（ https://blogs.msdn.microsoft.com/dotnet/2016/12/12/updating-visual-studio-2017-rc-net-core-tooling-improvements/ ），似乎解決方案不能再打開了。 我使用的代碼如下：

var workspace = MSBuildWorkspace.Create();
var solution = workspace.OpenSolutionAsync(slnPath).Result;

這是我得到的例外：

Microsoft.Build.Exceptions.InvalidProjectFileException
The default XML namespace of the project must be the MSBuild XML namespace. If the project is authored in the MSBuild 2003 format, please add xmlns="http://schemas.microsoft.com/developer/msbuild/2003" to the <Project> element. If the project has been authored in the old 1.0 or 1.2 format, please convert it to MSBuild 2003 format.
   at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject(String errorSubCategoryResourceName, IElementLocation elementLocation, String resourceName, Object[] args)
   at Microsoft.Build.Construction.ProjectParser.Parse()
   at Microsoft.Build.Construction.ProjectParser.Parse(XmlDocumentWithLocation document, ProjectRootElement projectRootElement)
   at Microsoft.Build.Construction.ProjectRootElement.Create(XmlReader xmlReader, ProjectCollection projectCollection)
   at Microsoft.CodeAnalysis.MSBuild.ProjectFileLoader.<LoadProjectAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.ProjectFileLoader.<LoadProjectFileAsync>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.MSBuildProjectLoader.<LoadProjectAsync>d__23.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.MSBuildProjectLoader.<GetOrLoadProjectAsync>d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.MSBuildProjectLoader.<LoadSolutionInfoAsync>d__18.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.MSBuildWorkspace.<OpenSolutionAsync>d__18.MoveNext()

在我看來，新的csproj結構並不完全支持。 一個可能的解決方案可能是在沒有轉換項目的情況下創建單獨的解決方案，但它確實是一種解決方法。 有任何想法嗎？

編輯：

我試圖按照錯誤消息中的建議，即添加xmlns屬性，如下所示：

<Project Sdk="Microsoft.NET.Sdk.Web" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <TargetFramework>net452</TargetFramework>
    <RuntimeIdentifier>win7-x86</RuntimeIdentifier>
    <GenerateDocumentationFile>true</GenerateDocumentationFile>
    <PreserveCompilationContext>true</PreserveCompilationContext>
    <AssemblyName>Arcmedia.Esl.WebApp.Api</AssemblyName>
    <OutputType>Exe</OutputType>
    <PackageId>Arcmedia.Esl.WebApp.Api</PackageId>
  </PropertyGroup>
  <ItemGroup>
    <None Include="App.config" />
    <Content Update="wwwroot;web.config">
      <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
    </Content>
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Hosting" Version="1.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.Hosting.Abstractions" Version="1.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.Server.IISIntegration" Version="1.1.0" />
    <PackageReference Include="Microsoft.AspNetCore.Server.Kestrel" Version="1.1.0" />
  </ItemGroup>
  <ItemGroup Condition=" '$(TargetFramework)' == 'net452' ">
    <Reference Include="System" />
    <Reference Include="Microsoft.CSharp" />
  </ItemGroup>
  <ItemGroup>
    <ProjectReference Include="..\xyz\abc.def.csproj" />
  </ItemGroup>
</Project>

但這並沒有解決問題，因為現在我得到另一個例外：

Microsoft.Build.Exceptions.InvalidProjectFileException
The attribute "Update" in element <Content> is unrecognized.
   at Microsoft.Build.Shared.ProjectErrorUtilities.ThrowInvalidProject(String errorSubCategoryResourceName, IElementLocation elementLocation, String resourceName, Object[] args)
   at Microsoft.Build.Internal.ProjectXmlUtilities.ThrowProjectInvalidAttribute(XmlAttributeWithLocation attribute)
   at Microsoft.Build.Internal.ProjectXmlUtilities.VerifyThrowProjectAttributes(XmlElementWithLocation element, String[] validAttributes)
   at Microsoft.Build.Construction.ProjectParser.ParseProjectItemElement(XmlElementWithLocation element, ProjectItemGroupElement parent)
   at Microsoft.Build.Construction.ProjectParser.ParseProjectItemGroupElement(XmlElementWithLocation element, ProjectElementContainer parent)
   at Microsoft.Build.Construction.ProjectParser.ParseProjectRootElementChildren(XmlElementWithLocation element)
   at Microsoft.Build.Construction.ProjectParser.Parse()
   at Microsoft.Build.Construction.ProjectParser.Parse(XmlDocumentWithLocation document, ProjectRootElement projectRootElement)
   at Microsoft.Build.Construction.ProjectRootElement.Create(XmlReader xmlReader, ProjectCollection projectCollection)
   at Microsoft.CodeAnalysis.MSBuild.ProjectFileLoader.<LoadProjectAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.ProjectFileLoader.<LoadProjectFileAsync>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.MSBuildProjectLoader.<LoadProjectAsync>d__23.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.MSBuildProjectLoader.<GetOrLoadProjectAsync>d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.MSBuildProjectLoader.<LoadSolutionInfoAsync>d__18.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.CodeAnalysis.MSBuild.MSBuildWorkspace.<OpenSolutionAsync>d__18.MoveNext()

所以，回到我原來的結論，似乎在嘗試使用Microsoft.CodeAnalysis.MSBuild.MSBuildWorkspace.OpenSolutionAsync時，沒有正確支持新的簡化csproj文件結構。

Answer 1

問題出現是因為項目文件正在使用VS2017 csproj的新架構格式，但msbuild正在您的計算機上從較舊的安裝（可能是VS2015）運行。 發生這種情況是因為您擁有的Roslyn MSBuildWorkspace是針對以前版本的MSBuild API構建的，該版本不了解新格式並且在您的計算機上使用該版本而不是更新版本。 如果您在計算機上沒有舊版本，則MSBuildWorkspace會立即因類型加載異常而失敗。

MSBuildWorkspace已經更新到較新的VS2017版本，但它還沒有在nuget上。 您可以從Roslyn myget Feed中獲取。

有關更多詳細信息，請查看此github問題： https ： //github.com/dotnet/roslyn/issues/16886