“ ViewBag”名称在当前上下文中不存在

我试图在我的应用程序中使用 ViewBag，我有所有最近的 dls，最新版本的 MVC 3，但我仍然得到错误:

“‘ ViewBag’名称在当前上下文中不存在”

我甚至卸载，然后重新安装 MVC 3，但是没有改变。

还有，我不相信 DLL 会出现在 GAC 上。

我的问题是什么? 或者如何将 dll 加入到 GAC 中？

144431 次浏览
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最佳答案

You need to add the MVC-specific Razor configuration to your web.config. See here: Razor HtmlHelper Extensions (or other namespaces for views) Not Found

Use the MVC 3 upgrade tool to automatically ensure you have the right config values.

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Try to Clean and rebuild. It worked in my case.

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I was having the same problem. Turned out I was missing the ./Views/Web.config file, because I created the project from an empty ASP.NET application instead of using an ASP.NET MVC template.

For ASP.NET MVC 5, a vanilla ./Views/Web.config file contains the following:

<?xml version="1.0"?>


<!-- https://stackoverflow.com/a/19899269/178082 -->
<configuration>
<configSections>
<sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Razor.Configuration.RazorWebSectionGroup, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section name="host" type="System.Web.WebPages.Razor.Configuration.HostSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
<section name="pages" type="System.Web.WebPages.Razor.Configuration.RazorPagesSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
</sectionGroup>
</configSections>


<system.web.webPages.razor>
<host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<pages pageBaseType="System.Web.Mvc.WebViewPage">
<namespaces>
<add namespace="System.Web.Mvc" />
<add namespace="System.Web.Mvc.Ajax" />
<add namespace="System.Web.Mvc.Html" />
<add namespace="System.Web.Routing" />
</namespaces>
</pages>
</system.web.webPages.razor>


<appSettings>
<add key="webpages:Enabled" value="false" />
</appSettings>


<system.web>
<httpHandlers>
<add path="*" verb="*" type="System.Web.HttpNotFoundHandler"/>
</httpHandlers>


<!--
Enabling request validation in view pages would cause validation to occur
after the input has already been processed by the controller. By default
MVC performs request validation before a controller processes the input.
To change this behavior apply the ValidateInputAttribute to a
controller or action.
-->
<pages
validateRequest="false"
pageParserFilterType="System.Web.Mvc.ViewTypeParserFilter, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"
pageBaseType="System.Web.Mvc.ViewPage, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"
userControlBaseType="System.Web.Mvc.ViewUserControl, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<controls>
<add assembly="System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" namespace="System.Web.Mvc" tagPrefix="mvc" />
</controls>
</pages>
</system.web>


<system.webServer>
<validation validateIntegratedModeConfiguration="false" />


<handlers>
<remove name="BlockViewHandler"/>
<add name="BlockViewHandler" path="*" verb="*" preCondition="integratedMode" type="System.Web.HttpNotFoundHandler" />
</handlers>
</system.webServer>
</configuration>

Adding a ./Views/Web.config file containing this content fixed this problem for me.

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I had the same problem and crimbo gave me the right clue, it was caused by the ./Views/Web.config file which was present but not containing the right namespaces I guess...

I created a blank MVC5 project and imported its ./Views/Web.config into my existing project and the red waves under every ViewBag use are gone !

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If you use Visual Studio 2013 and you like use MVC 3, you get this error because Visual Studio 2013 does not support MVC 3 natively (even of you change ./Views/web.config), only MVC 4: https://msdn.microsoft.com/en-us/library/hh266747.aspx

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I had a ./Views/Web.Config file but this error happened after publishing the site. Turns out the build action property on the file was set to None instead of Content. Changing this to Content allowed publishing to work correctly.

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I had the same problem in a solution that had been upgraded to MVC 5 in Visual Studio 2015.

In the web.config file within the Views folder (not the root web.config), I updated the version number referred to in <configSections> from 2.0.0.0 to 3.0.0.0.

<configuration>
<configSections>
<sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Razor.Configuration.RazorWebSectionGroup, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section name="host" type="System.Web.WebPages.Razor.Configuration.HostSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
<section name="pages" type="System.Web.WebPages.Razor.Configuration.RazorPagesSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
</sectionGroup>
</configSections>
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I had this problem after changing the Application's Default namespace in the Properties dialog.

The ./Views/Web.Config contained a reference to the old namespace

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After trying different things, it turns out it was VS cache. You can resolve it by deleting the cache files located in:

C:\Users\your.name.here\AppData\Local\Microsoft\VisualStudio\14.0\ComponentModelCache

I closed my project, deleted the files on that path and reopened my project, cleaned the solution and built it again and the problem was solved

The files will be recreated when you next launch Visual Studio

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In my case, changing the webpage:Version to the proper value resolved my issue, for me the correct value was(2.0.0.0 instead of 3.0.0.0) : 

<appSettings>
<add key="webpages:Version" value="2.0.0.0"/>
<add key="webpages:Enabled" value="false"/>
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After trying all approaches, none of them worked for me since all I have was correct configurations. finally

Deleting all files from "temp" and "%temp%" from system helped to resolve this issue.

Open Run command(Windows+R) and type above strings and delete all temporary files.

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I updated webpages:Version under in ./Views/Web.Config folder but this setting was also present in web.config in root. Update both or remove from root web.config

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If you had tried all available answers and still cannot find the answer this might solve issue. If you have different solutions configurations like Debug, Release etc then set project output path to 'bin' and compile project. Revert change after compiling.

Project Output Path

VS looks for dlls in bin folder

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I had already tried deleting the bin and obj file and restarting VS and had no luck.

I've also had this issue many times and it's a pain to solve each time. Often it is due to the web.config file not having the correct version of one of the references. This means click on the reference in Visual Studio to see the version in the property tab, and then match it to the version in the web.config files.

Another way is (if possible) upgrade to a later version of the .net framework and then deleting bin/obj files and restarting Visual Studio. I can only assume it's changing something in the

A quick check of the diff between the csproj file doesn't actually show any major difference... But the differences it did show was (I've added (remove) to show the old line)

<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> (remove)
<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">


<TargetFrameworkVersion>v4.5</TargetFrameworkVersion>(remove)
<TargetFrameworkVersion>v4.6</TargetFrameworkVersion>

In the Web.Config file (not the one in View)

<add key="webpages:Version" value="2.0.0.0" /> (remove)
<add key="webpages:Version" value="3.0.0.0"/>

It also added (to the same web.config file) but I manually removed it

 <system.codedom>
<compilers>
<compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.CSharpCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:6 /nowarn:1659;1699;1701"/>
<compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.CodeDom.Providers.DotNetCompilerPlatform.VBCodeProvider, Microsoft.CodeDom.Providers.DotNetCompilerPlatform, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" warningLevel="4" compilerOptions="/langversion:14 /nowarn:41008 /define:_MYTYPE=\&quot;Web\&quot; /optionInfer+"/>
</compilers>
</system.codedom>

Finally, in the Package Manager Console, add update-package

Run the website locally and see any compilation errors which was fixed by my second paragraph (matching the versions of the references)

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As @Wilson Vallecilla already mentioned. Please do the below steps to delete the cache:

Please follow below path to discover the files:

C:\Users\your.name.here\AppData\Local\Microsoft\VisualStudio\14.0\ComponentModelCache

Delete all four files:

  • Microsoft.VisualStudio.Default.cache
  • Microsoft.VisualStudio.Default.catalogs
  • Microsoft.VisualStudio.Default.err
  • Microsoft.VisualStudio.Default.external

I closed my project, deleted the files on that path and reopened my project, cleaned the solution and built it again and the problem was solved

Deleting your Temporary ASP.NET Files also helps. C:\Users\your.name.here\AppData\Local\Temp\Temporary ASP.NET Files.

This works for me.

Thanks!

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For MVC5, in case you are building an application from scratch. You need to add a web.config file to the Views folder and paste the following code in it.

<?xml version="1.0"?>
<configuration>
<configSections>
<sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Razor.Configuration.RazorWebSectionGroup, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section name="host" type="System.Web.WebPages.Razor.Configuration.HostSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
<section name="pages" type="System.Web.WebPages.Razor.Configuration.RazorPagesSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
</sectionGroup>
</configSections>


<system.web.webPages.razor>
<host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<pages pageBaseType="System.Web.Mvc.WebViewPage">
<namespaces>
<add namespace="System.Web.Mvc" />
<add namespace="System.Web.Mvc.Ajax" />
<add namespace="System.Web.Mvc.Html" />
<add namespace="System.Web.Routing" />
</namespaces>
</pages>
</system.web.webPages.razor>
</configuration>

Note that for MVC 3 you will have to change version to 3.0.0.0 at 

<host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />

You may have to close and open the *.cshtml page again to see the changes.


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