The MSBuild scripting language

MSBuild is the Microsoft Build Engine. What might be less known is that it offers a scripting language. An MSBuild file is usually a script, orchestrating what happens during the build process.


The MSBuild scripting language concepts:

  • properties are variables; some are reserved; some are predefined by MSBuild during the build process; others are environment variables; and others are customized in MSBuild projects and props files
  • items are inputs in the build system, usually files - these are used to include or exclude files from the build process; each item has some metadata attached to it
  • tasks are atomic build operations, like “compile” or “copy file”; there are plenty built-in tasks, and you can define your own by extending Microsoft.Build.Utilities.Task; a task must be present inside a target in order to be executed
  • targets are groups of tasks to be executed together; they enable sections of the build process to be called from the command line with the -target: switch
    • targets can have attributes that specify the order of operations (InitialTargets; DependsOnTarget; BeforeTarget) - MSBuild uses this information to build a Direct Acyclic Graph of targets to execute
    • each target runs only once in a single build


MSBuild offers an XML scripting language. By convention, MSBuild files have a limited set of extensions. However, it is only a convention - any of the below files (or a simple .xml file) can hold the definition of MSBuild properties, tasks and targets. That being said, by convention there are three types of files:

  • project files (.csproj, .vbproj, .esproj etc)
  • target files (.target)
    • The Microsoft.NET.Sdk target file is referenced in .NET csproj files (<Project Sdk="Microsoft.NET.Sdk">)
    • The file is picked up by MSBuild as a customization file in the folder structure of your project
  • property files (.props)
    • The Directory.Build.props file can hold build config and is picked up by MSBuild

Tasks are normally kept in libraries (DLLs) which are referenced by other files. MSBuild files can import other MSBuild files. Usually target files reference other target files.

Microsoft offers very good documentation each of these MSBuild concepts.

Hello World script

Create a file, name it “hello.txt” and paste the content below.

<?xml version="1.0" encoding="utf-8"?>
	<Target Name="ExecuteArbitraryCode" AfterTargets="CoreBuild">
		<Warning Text="Hello, World!"/>

To execute it, run

dotnet msbuild hello.txt --verbosity:quiet

It will output

MSBuild version 17.4.0+18d5aef85 for .NET C:\blog\playground\hello.txt(4,3): warning : Hello, World!

Congratulations! You wrote your first MSBuild script.