Disable roslyn in IIS application

Question

I have a web site in IIS that has the roslyn compilers enabled in the web.config. This site has a legacy application under it for which I need to disable the roslyn compilers. I don't see a way to do this using the web.config under the application, is there some way to set this up so the legacy application does not use roslyn, but keep the legacy folder as an IIS application?

Answer 1

Since there is no <clear /> option on the compilers element in web.config what has to be done is to replace the compilers defined in the parent web.config:

  <system.codedom>
    <compilers>
        <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <providerOption name="CompilerVersion" value="v4.0"/>
            <providerOption name="WarnAsError" value="false"/>
        </compiler>
        <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" warningLevel="4" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <providerOption name="CompilerVersion" value="v4.0"/>
            <providerOption name="OptionInfer" value="true"/>
            <providerOption name="WarnAsError" value="false"/>
        </compiler>
    </compilers>
  </system.codedom>  

These are the compiler settings that worked for me, and I was able to use CompilerVersion of v4.0 in place of v3.5 using these definitions.

Here are some additional configurations I found for earlier versions:

2.0 framework:

   <compilers>
       <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=%ASSEMBLY_VERSION%, Culture=neutral, PublicKeyToken=%ECMA_PUBLICKEY%" warningLevel="1" />
       <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=%ASSEMBLY_VERSION%, Culture=neutral, PublicKeyToken=%ECMA_PUBLICKEY%" />
       <compiler language="js;jscript;javascript" extension=".js" type="Microsoft.JScript.JScriptCodeProvider, Microsoft.JScript, Version=8.0.1100.0, Culture=neutral, PublicKeyToken=%MICROSOFT_PUBLICKEY%" />
       <compiler language="vj#;vjs;vjsharp" extension=".jsl" type="Microsoft.VJSharp.VJSharpCodeProvider, VJSharpCodeProvider, Version=%ASSEMBLY_VERSION%, Culture=neutral, PublicKeyToken=%MICROSOFT_PUBLICKEY%" />
       <compiler language="c++;mc;cpp" extension=".h" type="Microsoft.VisualC.CppCodeProvider, CppCodeProvider, Version=8.0.0.0, Culture=neutral, PublicKeyToken=%MICROSOFT_PUBLICKEY%" />
   </compilers>

1.1 Framework (compilers may need to be outside <system.codedom />:

<compilers>
   <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" warningLevel="1"/>
   <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
   <compiler language="js;jscript;javascript" extension=".js" type="Microsoft.JScript.JScriptCodeProvider, Microsoft.JScript, Version=7.0.5000.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
   <compiler language="VJ#;VJS;VJSharp" extension=".jsl" type="Microsoft.VJSharp.VJSharpCodeProvider, VJSharpCodeProvider, Version=7.0.5000.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
</compilers>

1.0 Framework (compilers may need to be outside <system.codedom />:

<compilers>
    <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" warningLevel="1" />
    <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" />
    <compiler language="js;jscript;javascript" extension=".js" type="Microsoft.JScript.JScriptCodeProvider, Microsoft.JScript, Version=7.0.3300.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
</compilers>