Microsoft.DotNet.Common.Targets（262,5）：错误：对象引用未设置为对象的实例

我正在将库从.Net 4.5迁移到.net core 。 我已经安装了.xproj ，但是当我运行dotnet build出现错误：

Microsoft.DotNet.Common.Targets（262,5）：错误：Obje ct引用未设置为对象的实例。

这是我的project.json文件：

 { "version": "1.0.0", "frameworks": { "net45": { "frameworkAssemblies": { "System.Collections.Concurrent": { "type": "build" } } }, "netstandard1.6": { "imports": "dnxcore50", "dependencies": { "NETStandard.Library": "1.6.0" } } } } 

有什么我想念的吗？

Answer 1

从命令行运行dotnet restore ，但不是从Visual Studio 2015 Update 3运行。我怀疑这与私有nuget提要有关。

Answer 2

如果在远程服务器上的TFS构建上出现此错误，您仍可以手动运行dotnet restore 。

例如。 我切换到C:\BUILD-AGENT\_work\1\s\RR.CRM并运行了dotnet restore

还不太确定VS何时这样做或不做，但现在它是一个快速修复工作。

Answer 3

我在VS2015（社区）中从头开始创建ASP.NET MVC Core项目并更新到Core 1.1.1时遇到了同样的问题。 由于某些未知原因，Nuget不会更新100％的引用; 其中一些仍然是“落后”。

您可以在下面找到我的project.json文件

 { "dependencies": { "Microsoft.AspNetCore.Razor.Tools": { "version": "1.1.0-preview4-final", "type": "build" }, "Microsoft.AspNetCore.Routing": "1.1.1", "Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.1.1", "Microsoft.AspNetCore.Authentication.Cookies": "1.1.1", "Microsoft.AspNetCore.Diagnostics": "1.1.1", "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.1.1", "Microsoft.AspNetCore.Mvc": "1.1.2", "Microsoft.AspNetCore.Server.IISIntegration": "1.1.1", "Microsoft.AspNetCore.Server.Kestrel": "1.1.1", "Microsoft.AspNetCore.StaticFiles": "1.1.1", "Microsoft.EntityFrameworkCore.SqlServer": "1.1.1", "Microsoft.EntityFrameworkCore.SqlServer.Design": { "version": "1.1.1", "type": "build" }, "Microsoft.EntityFrameworkCore.Tools": { "version": "1.1.0", "type": "build" }, "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.1.1", "Microsoft.Extensions.Configuration.Json": "1.1.1", "Microsoft.Extensions.Configuration.UserSecrets": "1.1.1", "Microsoft.Extensions.Logging": "1.1.1", "Microsoft.Extensions.Logging.Console": "1.1.1", "Microsoft.Extensions.Logging.Debug": "1.1.1", "Microsoft.Extensions.Options.ConfigurationExtensions": "1.1.1", "Microsoft.NETCore.App": { "version": "1.1.1", "type": "platform" }, "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.1.0", "Microsoft.VisualStudio.Web.CodeGeneration.Tools": { "version": "1.1.0-preview4-final", "type": "build" }, "Microsoft.VisualStudio.Web.CodeGenerators.Mvc": { "version": "1.1.0", "type": "build" } }, "tools": { "BundlerMinifier.Core": "2.4.337", "Microsoft.AspNetCore.Razor.Tools": "1.1.0-preview4-final", "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final", "Microsoft.EntityFrameworkCore.Tools": "1.1.0", "Microsoft.Extensions.SecretManager.Tools": "1.0.0", "Microsoft.VisualStudio.Web.CodeGeneration.Tools": { "version": "1.1.0-preview4-final", "imports": [ "portable-net45+win8" ] } }, "frameworks": { "netcoreapp1.0": { "imports": [ "dotnet5.6", "portable-net45+win8" ] } }, "buildOptions": { "emitEntryPoint": true, "preserveCompilationContext": true }, "runtimeOptions": { "configProperties": { "System.GC.Server": true } }, "publishOptions": { "include": [ "wwwroot", "**/*.cshtml", "appsettings.json", "web.config" ] }, "scripts": { "prepublish": [ "bower install", "dotnet bundle" ], "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ] } } 

Microsoft.AspNetCore.Razor.Tools未正确更新。 Microsoft.VisualStudio.Web.CodeGeneration.Tools和Microsoft.VisualStudio.Web.CodeGenerators.Mvc也必须手动更新。