Transform configs (conditionally) after build

TransformConfig.msbuild

<Target Name="AfterBuild">
  <CallTarget Condition="$(IsAgentBuild)=='true'" Targets="TransformConfig" />
  <CallTarget Condition="!($(IsAgentBuild)=='true')" Targets="PreviewTransformedConfig" />
</Target>

<Target Name="TransformConfig">
  <ItemGroup>
    <DeleteAfterBuild Include="$(WebProjectOutputDir)\web.*.config"/>
  </ItemGroup>
  <TransformXml Source="web.config" Transform="$(ProjectConfigTransformFileName)" Destination="$(WebProjectOutputDir)\web.config" />
  <Delete Files="@(DeleteAfterBuild)" />
</Target>

<Target Name="PreviewTransformedConfig">
  <!--<PropertyGroup>
    <OutputDirectory>$(WebProjectOutputDir)\bin\$(Configuration)</OutputDirectory>
  </PropertyGroup>
  <MakeDir Directories="$(OutputDirectory)" />-->
  <TransformXml Source="web.config" Transform="$(ProjectConfigTransformFileName)" 
                Destination="$(WebProjectOutputDir)\bin\$(Configuration)\preview-$(ProjectConfigTransformFileName)" />
</Target>