使用VS2015工具安装.NET Core 1.0（预览版）后，我无法创建.NET核心类库项目

Question

I get this error message when I try to add a .NET core class library to my solution:

Error: this template attempted to load component assembly 'Microsoft.VisualStudio.ProjectSystem.DotNet.Wizard, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. For more information on this problem and how to enable this template, please see documentation on Customizing Project Templates.

An empty folder is created on disk but nothing is added to the solution.

My initial process consisted of:

1. Upgrading Visual Studio 2015 to update 3
2. Uninstalling the preview / rc bits of the .NET core and tooling
3. Downloading and installing the release version of .NET core with the preview tooling

I have tried the following after getting this error:

• Uninstalling and reinstalling .NET Core
• Repairing .NET core installation
• Uninstalling and reinstalling Visual Studio 2015 Professional w/update 3
  • And then uninstalling and reinstalling and repairing .NET Core yet again afterwards for good measure
• Executing devenv /setup as administrator

I shut down and restart after each step as well, but no dice.

What else can I try? I had the preview bits of .NET Core on the machine earlier but according to the installation instructions it should be enough to just uninstall them before installing the release files, which I did.

Is there a log file somewhere which may contain information about why the assembly fail to load?

I have two elements in my uninstall programs list that match "Core":

1. Microsoft .NET Core 1.0.0 - SDK Preview 2 (x64)
2. Microsoft .NET Core 1.0.0 - VS 2015 Tooling Preview 2

I also have this installed, which seems to have been installed together with the above bits:

1. Microsoft .NET Version Manager (x64) 1.0.0-rc1

These 3 elements are all dated as installed today. I think the preview and rc1 parts of the name comes from the fact that only the runtime was released as final but the tooling is still in preview.

I got the installation files from here - http://dot.net/core - so it seems to me that I should've already installed the right bits.

There are no updates lingering under the Visual Studio extensions and updates.

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Update 1: I did a full repair, which changed nothing.

I then tried to use the command line tool, dotnet , to create a project and that worked just fine, everything from dotnet new to dotnet run executed successfully and with the expected results.

I then tried copying the project.json file into a subdirectory of my existing solution, edited it to remove the entry point bit and then tried to manually add the project in VS2015, and I got this:

The 'DNX Project System' package did not load correctly.
The problem may have been caused by a configuration change or by the installation of another extension. You can get more information by examining the file 'C:\\Users\\lasse\\AppData\\Roaming\\Microsoft\\VisualStudio\\14.0\\ActivityLog.xml'.
Restarting Visual Studio could help resolve this issue.

The activity log it refers to can be found on my public dropbox (renamed to a .txt extension) here: ActivityLog.xml (.txt) .

Extracts from this file that may be interesting are:

<description>Performance warning: String load failed. Pkg:{98F77210-A364-4168-BAE6-4D46FA7E19FE} (DNX Project System) LANG:0409 ID:5011&#x000D;&#x000A;</description>
<description>LegacySitePackage failed for package [DNX Project System]Source: &apos;System.ComponentModel.Composition&apos; Description: No exports were found that match the constraint: &#x000A;&#x0009;ContractName&#x0009;Microsoft.VisualStudio.Web.ProjectSystem.Telemetry.ITelemetryProvider&#x000A;&#x0009;RequiredTypeIdentity&#x0009;Microsoft.VisualStudio.Web.ProjectSystem.Telemetry.ITelemetryProvider&#x000D;&#x000A;</description>
<description>SetSite failed for package [DNX Project System](null)</description>

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Update 2: I found another webpage detailing the same type of problem, only during the preview period, here:

Cannot Create ASP.NET Core RC 2 web project in VS 2015 . It has a screenshot of the same error message.

One troubleshooting step was to post the Help/About content, it is available on my public Dropbox here .

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Update 3: OK, the website above mentions that devenv.exe.config was missing a reference to the dll in question. I checked mine and sure enough it was missing. I did not try to manually add it yet, opting to rerun devenv /setup but now I'm noticing that this does not complete.

I renamed the config file first, and then reran devenv /config, it has been running for 2.5 minutes now and doesn't seem to have any motivation to complete.

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Update 4: Manually editing the config file and adding the dotnet.wizard package made Visual Studio able to create the project, but it was still not able to open it, still complaining about the DNX package.

I will try some of the troubleshooting tips in that other forumthread and see if they help.

Answer 1

I ran into a similar issue and was able to fix it by:

1. Modifying Visual Studio 2015 installation and unchecking Microsoft Web Developer Tools
2. Deleting C:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\IDE\\Extensions\\Microsoft\\Web Tools\\DNX folder that was left from a previous version of the tools.
3. Deleting %LocalAppData%\\Microsoft\\VisualStudio\\14.0\\ComponentModelCache
4. Deleting %LocalAppData%\\Microsoft\\VisualStudio\\14.0\\devenv.exe.config
5. Running repair on the preview2 tooling.

Answer 2

安装Visual Studio Installer Projects工具对我有所帮助