Applying Web.Config transformations outside of Web Deployment

Question

Is there a way to apply VS 2010 Web.Config transformations outside of web deployment, say during debugging? It would give me a great boost to be able to freely switch between different environments.

Answer 1

Yes, you can perform a Web.config transformation explicitly by invoking the TransformXml MSBuild task during the AfterBuild step in your project file.

Here's an example:

<UsingTask
    TaskName="TransformXml"
    AssemblyFile="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v10.0\Web\Microsoft.Web.Publishing.Tasks.dll" />

<Target Name="AfterBuild" Condition="exists('Web.$(Configuration).config')">
    <!-- Generates the transformed Web.config in the intermediate directory -->
    <TransformXml
        Source="Web.config"
        Destination="$(IntermediateOutputPath)Web.config"
        Transform="Web.$(Configuration).config" />
    <!-- Overwrites the original Web.config with the transformed configuration file -->
    <Copy
        SourceFiles="$(IntermediateOutputPath)Web.config"
        DestinationFolder="$(ProjectDir)" />        
</Target>

Related resources:

• Web.config transformations for App.config files
• Can I specify that a package should be created every time I build a solution?

Answer 2

The solution above made a great starting point for me, but I ended up with the following which doesn't need a copy task and doesn't have any issues with file in use errors.

<UsingTask TaskName="TransformXml" AssemblyFile="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v10.0\Web\Microsoft.Web.Publishing.Tasks.dll" />
<Target Name="AfterBuild">
  <TransformXml Condition="exists('$(TempBuildDir)\Web.$(Configuration).config')" Source="$(TempBuildDir)\Web.config" Destination="$(OutputPath)Web.config" Transform="$(TempBuildDir)\Web.$(Configuration).config" />
  <ItemGroup>
    <DeleteAfterBuild Include="$(OutputPath)Web.*.config" />
  </ItemGroup>
  <Delete Files="@(DeleteAfterBuild)">
    <Output TaskParameter="DeletedFiles" PropertyName="deleted" />
  </Delete>
  <Message Text="DELETED FILES: $(deleted)" Importance="high" />
</Target>