By now, you may have noticed a .csproj file in your C# project folders. This is a C# Project file type. It contains instructions on how to build the project. Visual Studio includes another Microsoft program called MSBuild. MSBuild creates the code to build your application so that it can be run.

An automated build tool, such as MSBuild, is responsible for tasks like:

  1. Compiling the source code
  2. Managing dependencies
  3. Testing protocol
  4. Packaging the executable program for deployment

MSBuild is included in the Visual Studio IDE and has so far been doing its work under the radar. Other build tools are available for us to use in C# projects. However, like in the unit testing chapter, we will stick to the tools provided to us with the Visual Studio IDE.

For more on MSBuild, check out the documentation .

The Project File

The .csproj file is dynamically generated by MSBuild when the application is built. The file is written in XML (Extensible Markup Language). XML is another member of the markup language family, like HTML. It is most often used for transferring data.

The four principal elements of a project file are:

  1. Tasks: Units of executable code. Any build action that needs to take place will be done via tasks. The other elements pass information into tasks.
  2. Targets: Group and order related tasks for execution.
  3. Properties: Key/value pairs used for build configuration information.
  4. Items: Used to input resources, such as files, into the build system.

So far, in our simple projects, there is not much complexity in what MSBuild and the .csproj file need to do. Our C# code is designed to be tested and executed within the IDE with very few dependencies. When you are working as a C# developer on the job, things will start to get more complicated. You will likely need at least three target environments for your application:

  1. debugging in the IDE.
  2. a development server for testing your deployed program before it is released to the user.
  3. the final production environment.

The .csproj file is where any project dependencies are stored and also organized.
These will have different responsibilities in those different environments. So while we don’t do much with the project file yet, we will later on.

The four elements summarized above provide the details needed to manage larger projects.

To view a project file, right click on the project’s name in the Visual Studio file menu. From the dropdown menu, select Edit Project File.

User selecting

Most of our project files from this class will look like this:

   <Project Sdk="Microsoft.NET.Sdk">



This project example contains two property elements: OutputType and TargetFramework.

  • <OutputType> specifies the format of the build’s output. OutputType is the key, and Exe is the value. This build outputs an .exe file.
  • <TargetFramework> provides the version of .NET Core that the program uses.

Both of these properties are wrapped in a <PropertyGroup> element. In fact, all property elements must be nested within a <PropertyGroup> tag. Finally, <Project> is a special element that forms the base of all project files.

Check Your Understanding


What is the language of the C# project file?

  1. MSBuild
  2. C#
  3. csproj
  4. XML

What is the element type used for the individual units of the build process?

  1. item
  2. task
  3. property
  4. target