找不到类型或命名空间名称“系统" [英] The type or namespace name 'System' could not be found

问题描述

在 Visual Studio 2015 Professional 中打开我的项目时，我的所有视图 (*.cshtml) 中都出现以下错误(以及更多错误).

I have the following errors (and more) in all my views (*.cshtml) when opening my project in Visual Studio 2015 Professional.

错误 CS0246 找不到类型或命名空间名称System"(您是否缺少 using 指令或程序集引用?)严重性代码描述项目文件行

Error CS0246 The type or namespace name 'System' could not be found (are you missing a using directive or an assembly reference?) Severity Code Description Project File Line

错误 CS0518 未定义或导入预定义类型System.Object"严重性代码描述项目文件行

Error CS0518 Predefined type 'System.Object' is not defined or imported Severity Code Description Project File Line

错误 CS0518 未定义或导入预定义类型System.String"

Error CS0518 Predefined type 'System.String' is not defined or imported

我得到了这些参考:

<ItemGroup>
<Reference Include="Microsoft.CSharp" />
<Reference Include="Sitecore.Kernel, Version=7.0.0.0, Culture=neutral, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>N:XXXSitecore.Kernel.dll</HintPath>
</Reference>
<Reference Include="Sitecore.Mvc">
  <HintPath>N:XXXSitecore.Mvc.dll</HintPath>
</Reference>
<Reference Include="System.Web.DynamicData" />
<Reference Include="System.Web.Entity" />
<Reference Include="System.Web.ApplicationServices" />
<Reference Include="System.ComponentModel.DataAnnotations" />
<Reference Include="System" />
<Reference Include="System.Data" />
<Reference Include="System.Core" />
<Reference Include="System.Data.DataSetExtensions" />
<Reference Include="System.Web.Extensions" />
<Reference Include="System.Web.Helpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>N:XXXSystem.Web.Helpers.dll</HintPath>
</Reference>
<Reference Include="System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>N:XXXSystem.Web.Mvc.dll</HintPath>
</Reference>
<Reference Include="System.Web.Providers">
  <HintPath>N:XXXSystem.Web.Providers.dll</HintPath>
</Reference>
<Reference Include="System.Web.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>N:XXXSystem.Web.Razor.dll</HintPath>
</Reference>
<Reference Include="System.Web.WebPages, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>N:XXXSystem.Web.WebPages.dll</HintPath>
</Reference>
<Reference Include="System.Web.WebPages.Deployment, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>N:XXXSystem.Web.WebPages.Deployment.dll</HintPath>
</Reference>
<Reference Include="System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
  <SpecificVersion>False</SpecificVersion>
  <HintPath>N:XXXSystem.Web.WebPages.Razor.dll</HintPath>
</Reference>
<Reference Include="System.Xml.Linq" />
<Reference Include="System.Drawing" />
<Reference Include="System.Web" />
<Reference Include="System.Xml" />
<Reference Include="System.Configuration" />
<Reference Include="System.Web.Services" />
<Reference Include="System.EnterpriseServices" />

我发现一些解决方案说没有引用 mscorlib ..但是当我尝试添加它时，它说它已经存在(即使我没有在 csproj 文件中看到它).

I found some solutions saying that a mscorlib wasn't referenced.. but when I tried to add it it sayd that it's already there (even though I don't see it on the csproj file).

System.dll 引用:

System.dll reference:

解决方案:

解决了问题.. 我将构建路径设置为c:...in"而不是in".我相信这是因为我在项目的根目录中没有任何 web.config，所以 VS 没有将我的项目识别为 web 项目.

Managed the issue.. I had the build path set to a "c:...in" instead of "in". I believe this happened because I don't have any web.config in the root of the project, so VS didn't identify my project as a web project.

推荐答案

当我在 Visual Studio 2013 中创建解决方案然后尝试在 vs 2015 中构建它时，我尝试重新创建您的问题并提出了类似的错误.

I attempted to re-create your issue and came up with a similar error when the solution was created in visual studio 2013 and then tried building it in in vs 2015.

重新安装 NuGet 包管理器(并关闭，然后重新打开 VS 2015)后，我能够成功构建.

I was able to get a successful build once I reinstalled NuGet Package Manager (and closed, then reopened VS 2015).

参考文献/信用

有几个与通过早期版本的 NPM for VS 2015 构建问题相关的 SO 问题(即我只是传递我已经尝试和解决的问题).重复解决方案通常是更新/重新安装 NPM 或更改 Power Shell 中的执行策略.我倾向于喜欢更新 + 重新启动的方法，以避免修补 Windows 中的黑框.一个来源:https://stackoverflow.com/a/32251092/1158842也可能是MSBuild集成解决方案的问题，在这种情况下，从解决方案中的 NuGet 资源迁移出去就可以了.

There are several SO questions relating to build issues via with earlier version of NPM for VS 2015 (i.e. I'm just passing along what I've tried and worked out). Recurring resolution is usually update / reinstall NPM or change execution policy in power shell. I tend to like the update + restart approach to avoid tinkering with the black boxes in windows. one source: https://stackoverflow.com/a/32251092/1158842 There may also be an issue of MSBuild Integrated solutions, in which case migrating away from the NuGet resources in the solution could do the trick.

来源:https://stackoverflow.com/a/31811461/1158842

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