Specify assembly version number as a command line argument in MSBuild

Question

I would like to be able to specify the version number for all assemblies to be generated during a build as a MSBuild command argument like this:

MSBuild.exe /p:version=5.4.3.0 

I have looked over AssemblyInfoTask but it does not seem to me like a good solution in this case.

Answer 1

For SDK-style projects that are built using dotnet.exe, assembly version attributes are generated automatically, so you can use /p:Version=5.4.3.0 right out of the box.

If you use the old project format, you need to add the following BeforeBuild step to your .csproj file. No need to use extra .targets and extension packs, because MSBuild already has a nice built-in task which does most of the stuff:

<Target Name="BeforeBuild">
  <ItemGroup>
    <AssemblyAttributes Include="AssemblyVersion">
      <_Parameter1>$(Version)</_Parameter1>
    </AssemblyAttributes>
  </ItemGroup>
  <MakeDir Directories="$(IntermediateOutputPath)" />
  <WriteCodeFragment Language="C#"
                     OutputFile="$(IntermediateOutputPath)Version.cs"
                     AssemblyAttributes="@(AssemblyAttributes)" />
  <ItemGroup>
    <Compile Include="$(IntermediateOutputPath)Version.cs" />
  </ItemGroup>
</Target>

Just make sure you remove the existing AssemblyVersion attribute because it will now be generated during build.

Update 7/29/2020: Michael Parker has pointed out that if you use this approach and do a build from Visual Studio, you end up with an empty version in the Version.cs file. To overcome this, I suggest defining the default Version value in your .csproj file as follows:

<PropertyGroup>
  ...
  <Version Condition="'$(Version)' == ''">1.0.0.0</Version>
</PropertyGroup>

This will set it to 1.0.0.0 if Version wasn't specified in the command line.