This document discusses project files and MSBuild. It explains that project files are MSBuild files that define properties, items, imports and targets. It compares legacy project files to SDK-style project files. It also discusses how MSBuild works by parsing the project file and evaluating properties, items, imports and targets. Finally, it recommends using build logging to see how MSBuild evaluates the project file.

1. Things (I think) you
should know
about project files and MSBuildDavid Wengier
Developer - .NET Project System
Microsoft
@davidwengier twitch.tv/davidwengier

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What is a Project System?
Project
System
Test Explorer
MSBuild
VS API (DTE)
Debugger
Solution Explorer
Compiler

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What is a project file?

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A project file is an MSBuild
file.

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Legacy vs SDK-style

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net472</TargetFramework>
</PropertyGroup>
</Project>
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Import
Project="$(MSBuildExtensionsPath)$(MSBuildToolsVersion)Microsoft.Common.props"
Condition="Exists('$(MSBuildExtensionsPath)$(MSBuildToolsVersion)Microsoft.Common.props
')" />
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
<ProjectGuid>{6656A70A-50E8-40A0-996B-81489FB455BE}</ProjectGuid>
<OutputType>Exe</OutputType>
<RootNamespace>ConsoleApp9</RootNamespace>
<AssemblyName>ConsoleApp9</AssemblyName>
<TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
<FileAlignment>512</FileAlignment>
<AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
<Deterministic>true</Deterministic>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
<PlatformTarget>AnyCPU</PlatformTarget>
<DebugSymbols>true</DebugSymbols>
<DebugType>full</DebugType>
<Optimize>false</Optimize>
<OutputPath>binDebug</OutputPath>
<DefineConstants>DEBUG;TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
<PlatformTarget>AnyCPU</PlatformTarget>
<DebugType>pdbonly</DebugType>
<Optimize>true</Optimize>
<OutputPath>binRelease</OutputPath>
<DefineConstants>TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
</PropertyGroup>
<ItemGroup>
<Reference Include="System" />
<Reference Include="System.Core" />
<Reference Include="System.Xml.Linq" />
<Reference Include="System.Data.DataSetExtensions" />
<Reference Include="Microsoft.CSharp" />
<Reference Include="System.Data" />
<Reference Include="System.Net.Http" />
<Reference Include="System.Xml" />
</ItemGroup>
<ItemGroup>
<Compile Include="Program.cs" />
<Compile Include="PropertiesAssemblyInfo.cs" />
</ItemGroup>
<ItemGroup>
<None Include="App.config" />
</ItemGroup>
<Import Project="$(MSBuildToolsPath)Microsoft.CSharp.targets" />
</Project>

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Imports and Sdks

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<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net472</TargetFramework>
</PropertyGroup>
</Project>
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<Import
Project="$(MSBuildExtensionsPath)$(MSBuildToolsVersion)Microsoft.Common.props"
Condition="Exists('$(MSBuildExtensionsPath)$(MSBuildToolsVersion)Microsoft.Common.props
')" />
<PropertyGroup>
<Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
<Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
<ProjectGuid>{6656A70A-50E8-40A0-996B-81489FB455BE}</ProjectGuid>
<OutputType>Exe</OutputType>
<RootNamespace>ConsoleApp9</RootNamespace>
<AssemblyName>ConsoleApp9</AssemblyName>
<TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
<FileAlignment>512</FileAlignment>
<AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
<Deterministic>true</Deterministic>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
<PlatformTarget>AnyCPU</PlatformTarget>
<DebugSymbols>true</DebugSymbols>
<DebugType>full</DebugType>
<Optimize>false</Optimize>
<OutputPath>binDebug</OutputPath>
<DefineConstants>DEBUG;TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
</PropertyGroup>
<PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
<PlatformTarget>AnyCPU</PlatformTarget>
<DebugType>pdbonly</DebugType>
<Optimize>true</Optimize>
<OutputPath>binRelease</OutputPath>
<DefineConstants>TRACE</DefineConstants>
<ErrorReport>prompt</ErrorReport>
<WarningLevel>4</WarningLevel>
</PropertyGroup>
<ItemGroup>
<Reference Include="System" />
<Reference Include="System.Core" />
<Reference Include="System.Xml.Linq" />
<Reference Include="System.Data.DataSetExtensions" />
<Reference Include="Microsoft.CSharp" />
<Reference Include="System.Data" />
<Reference Include="System.Net.Http" />
<Reference Include="System.Xml" />
</ItemGroup>
<ItemGroup>
<Compile Include="Program.cs" />
<Compile Include="PropertiesAssemblyInfo.cs" />
</ItemGroup>
<ItemGroup>
<None Include="App.config" />
</ItemGroup>
<Import Project="$(MSBuildToolsPath)Microsoft.CSharp.targets" />
</Project>

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Implicit imports

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How does MSBuild work?
You can ignore this bit if you already know.

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The biggest simplification ever:
public class Project
{
public Dictionary<string, string> Properties { get; set; }
public Dictionary<string, Dictionary<string, string>> Items { get; set; }
}

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The biggest simplification ever, cont:
<Project>
<PropertyGroup>
<Foo>Bar</Foo>
</PropertyGroup>
<ItemGroup>
<Compile Include="Main.cs“ MyMetadata="Zam" />
</ItemGroup>
</Project>
<Project>
<PropertyGroup>
<Foo>Baz</Foo>
</PropertyGroup>
<ItemGroup>
<Compile Update="Main.cs" MyMetadata="Zim" />
</ItemGroup>
</Project>

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The biggest simplification ever, cont:
<Project>
<PropertyGroup>
<Foo>Baz</Foo>
</PropertyGroup>
<ItemGroup>
<Compile Update="Main.cs" MyMetadata="Zim" />
</ItemGroup>
</Project>
<Project>
<PropertyGroup>
<Foo>Bar</Foo>
</PropertyGroup>
<ItemGroup>
<Compile Include="Main.cs" MyMetadata="Zam" />
</ItemGroup>
</Project>

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Code reuse in project files

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Better package references

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What MSBuild sees

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Performance Summary

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Build logging

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VS Build logging

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Imports Tree

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In summary:
• Project files are MSBuild files
• Project files are code
• Code reuse (Import)
• Separation of concerns (Import, Include vs Update)
• Order is important
• Use /pp or /bl to see what is going on
• Stuff we didn’t cover:
• Function calls (Tasks)
• Variables (properties)
• Conditionals (condition)

22. Thank You
@davidwengier twitch.tv/davidwengier