MVC 3 error in VS2017: The name 'ViewData' does not exist in the current context

Perhaps this is an Intellisense issue, as it only occurs in .cshtml files and the code compiles/executes normally. I'm not sure.

I recently migrated from VS2010 to VS2017 and I'm trying to work with an MVC3 project. Everything runs fine, but I'm getting multiple Intellisense errors related to the MVC syntax. For example in Views > Shared > _Layout.cshtml:

<title>@ViewData["Title"]</title>

Gives the error:

The name 'ViewData' does not exist in the current context

This is set by Views > Home > Index.cshtml:

    @{
        ViewData.Title = "Dashboard"; // intellisense error also shows here
    }

This similarly occurs when trying to use @Html.Partial:

'HtmlHelper' does not contain a definition for 'Partial' and no extension method 'Partial' accepting a first argument of type 'HtmlHelper' could be found (are you missing a using directive or an assembly reference?)

I'm not sure if there's some sort of issue with my dll references or web config. I've verified the following dll references are present:

System.Web.Mvc - Version 3.0.0.0
System.Web.Razor - Version 2.0.0.0
System.Web.WebPages - Version 1.0.0.0
System.Web.WebPages.Razor - Version 1.0.0.0

In my Views/web.config file:

  <configSections>
    <sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Razor.Configuration.RazorWebSectionGroup, System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
      <section name="host" type="System.Web.WebPages.Razor.Configuration.HostSection, System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
      <section name="pages" type="System.Web.WebPages.Razor.Configuration.RazorPagesSection, System.Web.WebPages.Razor, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />
    </sectionGroup>
  </configSections>

  <system.web.webPages.razor>
    <host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=3.0.0.0, 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" />
        <add namespace="System.Web.Optimization" />
      </namespaces>
    </pages>
  </system.web.webPages.razor>

And my root web.config file:

<compilation debug="true" targetFramework="4.0">
  <assemblies>
    <add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <add assembly="System.Web.Helpers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <add assembly="System.Web.Routing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <add assembly="System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <add assembly="System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
  </assemblies>
</compilation>

<pages>
  <namespaces>
    <add namespace="System.Web.Helpers" />
    <add namespace="System.Web.Mvc" />
    <add namespace="System.Web.Mvc.Ajax" />
    <add namespace="System.Web.Mvc.Html" />
    <add namespace="System.Web.Routing" />
    <add namespace="System.Web.WebPages" />
  </namespaces>
</pages>

<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
  <dependentAssembly>
    <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
    <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="3.0.0.0" />
  </dependentAssembly>
  <dependentAssembly>
    <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-1.5.2.14234" newVersion="1.5.2.14234" />
  </dependentAssembly>
</assemblyBinding>