allowDefinition='MachineToApplication' error setting <MvcBuildViews>true</MvcBuildViews>

Question

In my Asp.Net MVC 4 project, I've set in the .csproj file to build the view <MvcBuildViews>true</MvcBuildViews>. The problem is that building the project I got the error:

It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. This error can be caused by a virtual directory not being configured as an application in IIS.

I tried to delete the obj folder but the error keep raising. The error specify that the problem is in the authentication tag row:

<system.web>
    <authentication mode="Forms">
      <forms loginUrl="~/Account/Login" timeout="2880" />
    </authentication>

Often, I'm able to run the application by running the application (I got the error), building the app and after that running again.

Answer 1

Doing what @matrixugly suggests will fix the issue, but will also cause the compile-time view checking to stop working as well. I am assuming you still want to error check your views at compile time? If that is the case, better fixes below.

In order to understand why these solutions work, we have to first know how the problem is created:

1. The developer wants compile-time checking on views, so they set MvcBuildViews=true.
2. The application builds fine, UNTIL they publish the project.
3. Subsequent attempts to build the project result in a compile-time error: It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. This error can be caused by a virtual directory not being configured as an application in IIS.

So what causes this issue? When the project is published the compiler, by default it uses <project-dir>\obj\ to place copies of the source files that it will work with. Unfortunately, these files are not automatically deleted when publishing is complete. The next time the developer compiles the project with MvcBuildViews=true, it will error out because the aspnet compiler includes the obj\ folder during compilation, since it is underneath the <project-dir> folder.

So how do we fix this? Well, you have four options:

1. Set MvcBuildViews=false. I don't really consider this a solution, so let's move on.
2. Delete the files in <project-dir>\obj\. Works, but can be a hassle since it has to be done after every publish.

3. Change the path that publishing uses as an intermediate directory through the use of the <BaseIntermediateOutputPath> property in your project config file.
   
   Example (Ref: this link):
   

   <BaseIntermediateOutputPath> [SomeKnownLocationIHaveAccessTo] </BaseIntermediateOutputPath>

4. Add a new section in your project config file that deletes the offending files for you on build (reference Microsoft Connect). I've even made it easy for you, just copy and paste:

   <PropertyGroup>
   <_EnableCleanOnBuildForMvcViews Condition=" '$(_EnableCleanOnBuildForMvcViews)'=='' ">true</_EnableCleanOnBuildForMvcViews>
   </PropertyGroup>
   <Target Name="CleanupForBuildMvcViews" Condition=" '$(_EnableCleanOnBuildForMvcViews)'=='true' and '$(MVCBuildViews)'=='true' " BeforeTargets="MvcBuildViews">
   <ItemGroup>
       <_TempWebConfigToDelete Include="$(BaseIntermediateOutputPath)**\Package\**\*" />
       <_TempWebConfigToDelete Include="$(BaseIntermediateOutputPath)**\TransformWebConfig\**\*" />
       <_TempWebConfigToDelete Include="$(BaseIntermediateOutputPath)**\CSAutoParameterize\**\*" />
       <_TempWebConfigToDelete Include="$(BaseIntermediateOutputPath)**\TempPE\**\*" />
   </ItemGroup>
   
   <Delete Files="@(_TempWebConfigToDelete)"/>
   </Target>
   

My recommendation would be to use either option 3 or 4.

N.B. For those that have never edited their project file, you can't edit it while loaded. It must first be unloaded by right clicking it and selecting Unload Project. You can then right-click the project and edit the project file. Alternatively, you can edit the file outside of Visual Studio.