MSBuild Basics

.NET 2.0 introduced a new tool called MSBuild. MSBuild is primarily used to build .NET applications, but can be used for other types of applications as well. From Windows Vista, MSBuild is distributed with Windows itself, making it a strong platform for implementing scripted application on non-developer PCs as well.

Before .NET 2.0, application were built by one or more of these strategies:

• Using the build menu from inside Visual Studio
• Using the devenv.exe process from the command line with some extra parameters
• Using a third-party tool like NAnt (which MSBuild is based on)

The drawback with the first two strategies was that they were hard to script. The drawback with the third solution was that two build environments had to be held in sync and maintained. .NET 2.0 Visual Studio projects are now implemented in the MSBuild language, but MSBuild has no dependencies on Visual Studio itself. MSBuild can, in theory, be implemented in files with any extension, but a number of formats seem to be the supported standard from Microsoft: csproj, vbproj, vcproj, vjsproj, proj, and .targets. The first four are different types of project files for Visual Studio, while the last two are new extensions, which are either written by hand or with a tool knowing the MSBuild syntax. A few tools exist for this purpose. My personal opinion is that building in xml editor in Visual Studio is quite good for this purpose. A repeating question among MSBuild developers is if you should extend the files generated by visual studio with new stuff, or whether you should write your own containing your home-made MSBuild scripts. My personal opinion is to let Visual Studio generate its own projects (example: csproj files) and create your home-made scripts in a .proj file with the same name as the project. I usually start the .proj file by implementing the three targets: Clean, Build and Rebuild, which basically just calls the similar targets in the .csproj file. This way, you avoid updating an auto-generated file which you don’t have control over.

An MSBuild file is implemented in XML. The root element of an MSBuild XML file will always be a project containing target elements. It is possible to run multiple targets in an MSBuild file. When the MSBuild script is started from the command line, it takes a build file as parameter as well as the names of the targets, which should be executed.

A target is implemented as a sequential list of tasks. The tasks are executed in the order in which they are specified beneath the target element. Both targets and tasks can be dependent on each other.

This is an example of a very simple file to build a .NET project:

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<?xml version="1.0" encoding="utf-8" ?> <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">   <Target Name="Build">     <Message Text="Building msbuildintro" />     <MSBuild Projects="msbuildintro.csproj" Targets="Build" />   </Target> </Project>

The example defines a project with the MSBuild namespace. Using the namespace helps you develop the build file in Visual Studio using Intellisense. The build file contains a single target named Build. This target contains two tasks: Message and MSBuild. Message outputs a message to the console and is used primarily for debugging purposes. MSBuild runs a configurable number of targets on another build file. Since the .csproj file is also implemented in MSBuild, we are able to call targets in the build file from the example build file. In this case, we call the target Build in the .csproj file. All projects generated by Visual Studio automatically implement the Clean, Build and Rebuild targets. These targets are actually executed when you select the similar commands in the Build menu from within Visual Studio.