TransformXml task could not be loaded from Microsoft.Web.Publishing.Tasks.dll

Question

Has anyone seen this error and know how to fix it?

The \"TransformXml\" task could not be loaded from the assembly C:\\Program Files (x86)\\MSBuild\\M

Answer 1

For me it started working just by adding reference to the NuGet package MSBuild.Microsoft.VisualStudio.Web.targets v14.0.0.3

Even no need to add UsingTask element to the project file as it mentioned by the package author

https://github.com/pdonald/nuget-webtargets

Just install the NuGet package. The package automatically sets the $(VSToolsPath) property to use the targets file in the tools folder.

And then I was able to use TransformXml and other tasks, defined in the package, for instance to transform app.config

  <Target Name="app_config_AfterCompile" AfterTargets="AfterCompile" Condition="Exists('app.$(Configuration).config')">
    <!--Generate transformed app config in the intermediate directory-->
    <TransformXml Source="app.config" Destination="$(IntermediateOutputPath)$(TargetFileName).config" Transform="app.$(Configuration).config" />
    <!--Force build process to use the transformed configuration file from now on.-->
    <ItemGroup>
      <AppConfigWithTargetPath Remove="App.config" />
      <AppConfigWithTargetPath Include="$(IntermediateOutputPath)$(TargetFileName).config">
        <TargetPath>$(TargetFileName).config</TargetPath>
      </AppConfigWithTargetPath>
    </ItemGroup>
  </Target>

Answer 2

You need two things to make it work:

1) Install Visual Studio Build Tools (You don't need the whole Visual Studio, only the VS Build Tools) with selected "Web development build tools" option on your build server https://www.visualstudio.com/pl/thank-you-downloading-visual-studio/?sku=BuildTools&rel=15

2) Ensure that path to Microsoft.Web.Publishing.Tasks.dll is correct

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

Answer 3

To get mine to work, I just copied my v10.0 folder and renamed it to v11.0, and things seems to work well from then on. That's the quick fix for now.

As this is probably not the best solution, and although it works, I was going to try installing the Microsoft Windows SDK for Windows 7 and .NET Framework 4 Windows SDK for Windows 7 and .NET Framework 4, but it is taking to long to download.

Answer 4

Just in case someone is using an SDK-style csproj, you can achieve this without having to install Visual Studio on the build server.

1. First you should install the SlowCheetah nuget package to your project. Once you install it, you'll see the following in your SDK-style project.

   <PackageReference Include="Microsoft.VisualStudio.SlowCheetah" Version="3.2.20">
           <PrivateAssets>all</PrivateAssets>
           <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
   </PackageReference>
   

2. Then make sure you add the GeneratePathProperty="true" attribute (see below). This is very important for the next part because it'll help you grab the path of where the nuget package is restored on your machine. George Dangl explains it in his article here.

   <PackageReference Include="Microsoft.VisualStudio.SlowCheetah" Version="3.2.20" GeneratePathProperty="true">
           <PrivateAssets>all</PrivateAssets>
           <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
   </PackageReference>
   

3. Import the SlowCheetah targets into your project:

   <Import Project="$(PkgMicrosoft_VisualStudio_SlowCheetah)\build\Microsoft.VisualStudio.SlowCheetah.targets" />
   

4. You can now use an target command (in this case after publish) to apply some custom transformations. If you need to, you can always hard-code the file names below instead of using the variables in the below example.

   <Target Name="AfterPublishs" AfterTargets="Publish">
        <TransformTask Source="Web.config" Transform="Web.$(Configuration).MyCustomTransformFile.config" Destination="$(PublishDir)\Web.config" />
   </Target>
   

If you haven't used SlowCheetah before, I recommend checking it out. They have a Visual Studio extension that will make it easier for you to preview transform files.