Most of the time when working with multiple projects in a solution I want to set the version globally using the Directory.Build.props file. That way I only have to update the version in one file, rather than all project files.
While this works great for SDK style projects, it doesn’t work well with .NET Framework projects. Basically, whatever value I have set in the .props file is read once when I open the solution and any changes are ignored until I close and reopen the solution.

As a workaround I use this small target in Directory.Build.targets to actively read the Version property from the .props file and write it into a separate version info file in every Framework project before every build.

Here’s a quick reminder regarding the two Directory.Build files.

---

<Target Name="SetAssemblyVersion" BeforeTargets="BeforeBuild"  Condition="'$(TargetFramework)'==''">
  <!-- Read the Version property from the .props file -->
  <XmlPeek XmlInputPath="$(MSBuildThisFileDirectory)Directory.Build.props" Query="/n:Project/n:PropertyGroup/n:Version/text()"
           Namespaces="&lt;Namespace Prefix='n' Uri='http://schemas.microsoft.com/developer/msbuild/2003' /&gt;">
    <Output TaskParameter="Result" ItemName="PropVersion"/>
  </XmlPeek>
 
  <!-- Prepare the attribute -->
  <ItemGroup>
    <AssemblyAttributes Include="AssemblyVersion">
      <_Parameter1>@(PropVersion)</_Parameter1>
    </AssemblyAttributes>
  </ItemGroup>
 
  <!-- Write the attribute -->
  <Message Importance="high" Text="Setting assembly version to '@(PropVersion)'" />
  <WriteCodeFragment Language="C#" OutputFile="Properties\AssemblyVersion.cs" AssemblyAttributes="@(AssemblyAttributes)" />
</Target>

Since MSBuild files are basically just XML, we can use XmlPeek to read the content of the Version property. Don’t forget the namespace!
Since the .props and .targets files are right next to each other, we can use the predefined MSBuildThisFileDirectory property to find the path to the .props file.

Then we take that information and write it in a standalone file next to the AssemblyInfo.cs file you get by default. Keep in mind that the target is executed for the project, meaning the path is relative to the .csproject file.
Also remember to remove the AssemblyVersion from the existing AssemblyInfo.cs to avoid errors.

Lastly, we don’t want to run this target for SDK style projects. One of the easiest ways to avoid that is to check the TargetFramework property in the condition.