Question

I’m looking at a web.config right now in ASP.NET WebForms .NET 3.5 that’s got all the primary config files broken out like thus:

<configuration>
<system.web>
    <membership configSource="config\membership.config"/>
    <authentication configSource="config\authentication.config"/>
    <machineKey configSource="config\machineKey.config"/>
    <compilation debug="true">
        <assemblies>
            <add assembly="System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>
            <add assembly="System.Web.DataVisualization, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            <add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
            <add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            <add assembly="System.Data.DataSetExtensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
        </assemblies>
    </compilation>
    <customErrors mode="Off"/>
    <authorization>
        <deny users="?"/>
    </authorization>
    <roleManager enabled="true" cacheRolesInCookie="true"/>
    <pages configSource="config\pages.config"/>
    <httpHandlers configSource="config\httpHandlers.config"/>
    <httpModules configSource="config\httpModules.config"/>
    <webServices>
        <protocols>
            <add name="HttpGet"/>
            <add name="HttpPost"/>
        </protocols>
    </webServices>
</system.web>
</configuration>

and if I compile the source in VS 2010 it complains about not being able to find the .NET DataVisualization library (Error 14 Could not load file or assembly 'System.Web.DataVisualization, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified. sourcecodefile line) and if I compile it with the aspnet_compiler or just drop it in IIS, everything works fine.

How can I stop this from happening in VS?

Do I have to bring those config settings back into the web.config?

Casini doesn’t have a problem with this config, nor the IIS dev server, and the file is NOT in the GAC (not the 3.5 version anyways, the 4.0 is), and I won’t put it there for this one problem (I’ll move everything back into the web.config proper) and the dll file is in the bin folder.

Answer 1

You need to add a reference to the System.Web.DataVisualization assembly into your Visual Studio project. Visual Studio doesn’t compile against any assemblies not listed in the “References” folder.

In the Solution Explorer, under your project, right-click on the “References” folder and click “Add Reference…”

Select and add the missing assembly.

Problem solved.