C# – The type or namespace name does not exist in the namespace ‘System.Web.Mvc’

asp.net-mvc-3c++

Buiding MVC3 solution went well but have got an error in browser:

Compiler Error Message: CS0234: The type or namespace name 'Html' does not exist in the namespace 'System.Web.Mvc' (are you missing an assembly reference?)

Source Error:
Line 25:         <add namespace="System.Web.Mvc" />
Line 26:         <!--<add namespace="System.Web.Mvc.Ajax" />-->
Line 27:         <add namespace="System.Web.Mvc.Html" />
Line 28:         <add namespace="System.Web.Routing" />
Line 29:         <add namespace="System.Web.WebPages" />

I have installed packets for the solution with NuGet and set up for all projects MVC3. Does MVC3 include libraries System.Web.Mvc.Ajax, System.Web.Mvc.Html and others? Why am I getting the error?


In References folder, I have System.Web.Mvc

Runtime version: v4.0.30319,

Version: 3.0.0.0

Web.config

<?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=152368
  -->
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
  </configSections>
  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
    <add key="webpages:Version" value="1.0.0.0" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <authentication mode="Forms">
      <forms loginUrl="~/Account/LogOn" timeout="2880" />
    </authentication>
    <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>
    <httpRuntime targetFramework="4.5" encoderType="System.Web.Security.AntiXss.AntiXssEncoder, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
    <machineKey compatibilityMode="Framework45" />
    <profile defaultProvider="DefaultProfileProvider">
      <providers>
        <add name="DefaultProfileProvider" type="System.Web.Providers.DefaultProfileProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" />
      </providers>
    </profile>
    <membership defaultProvider="DefaultMembershipProvider">
      <providers>
        <add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" />
      </providers>
    </membership>
    <roleManager defaultProvider="DefaultRoleProvider">
      <providers>
        <add name="DefaultRoleProvider" type="System.Web.Providers.DefaultRoleProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" />
      </providers>
    </roleManager>
    <sessionState mode="InProc" customProvider="DefaultSessionProvider">
      <providers>
        <add name="DefaultSessionProvider" type="System.Web.Providers.DefaultSessionStateProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" />
      </providers>
    </sessionState>
  </system.web>
  <system.webServer>
    <validation validateIntegratedModeConfiguration="false" />
  </system.webServer>
  <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>
    </assemblyBinding>
  </runtime>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
  </entityFramework>
  <connectionStrings>
    <add name="EFDbContext" connectionString="Data Source=.\SQLEXPRESS;Initial Catalog=SportStore;Integrated Security=True;Pooling=False;" providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>

MSDN the System.Web.Mvc namespace

file packages.config:

<?xml version="1.0" encoding="utf-8"?>
<packages>
  <package id="EntityFramework" version="5.0.0-rc" />
  <package id="jQuery" version="1.7.2" />
  <package id="jQuery.UI.Combined" version="1.8.11" />
  <package id="jQuery.Validation" version="1.9" />
  <package id="Microsoft.AspNet.Mvc" version="3.0.20105.1" />
  <package id="Microsoft.AspNet.Providers.Core" version="1.0" />
  <package id="Microsoft.AspNet.Providers.LocalDB" version="1.0" />
  <package id="Microsoft.AspNet.Razor" version="1.0.20105.408" />
  <package id="Microsoft.AspNet.WebPages" version="1.0.20105.408" />
  <package id="Microsoft.Web.Infrastructure" version="1.0.0.0" />
  <package id="Modernizr" version="2.0.6" />
  <package id="Moq" version="4.0.10827" />
  <package id="Ninject" version="3.0.1.10" />
</packages>

Best Solution

Clean your solution and then set the property of those files to Copy Local = True.

To set the Copy Local property to True or False

In Solution Explorer, click the Show All Files button to display the References node.

  • Open the References node for the project.
  • Right-click a reference in the References list, and click Properties. The properties associated with that reference appear in a list in the Properties window.
  • In the Properties window, change the Copy Local property to True or False.