MSBuild target to write license expressions to an assembly attribute

license-attribute.targets

<Project>
    <!-- Create a target that will assign the license information for a project to an attribute -->
    <Target Name="AssignLicenseAttribute">
        <!-- Only do this if the user is allowing assemblyinfo generation -->
        <ItemGroup Condition="'$(GenerateAssemblyInfo)' == 'true'">
            <!-- Only generate if the license is present and the user has requested this attribute -->
            <AssemblyAttribute
                Include="System.Reflection.AssemblyMetadataAttribute"
                Condition="'$(GenerateLicenseExpressionAttribute)' == 'true' and '$(PackageLicenseExpression)' != ''">
                <_Parameter1>LicenseExpression</_Parameter1>
                <_Parameter2>$(PackageLicenseExpression)</_Parameter2>
            </AssemblyAttribute>
        </ItemGroup>
    </Target>

    <PropertyGroup>
        <!-- Default the attribute to 'on' but allow for user overrides -->
        <GenerateLicenseExpressionAttribute Condition="'$(GenerateLicenseExpressionAttribute)' == ''">true</GenerateLicenseExpressionAttribute>
        <!-- Tell the build to run our target before the build command (so we generate the attribute before compilation) -->
        <PrepareForBuildDependsOn>
            AssignLicenseAttribute;
            $(PrepareForBuildDependsOn)
        </PrepareForBuildDependsOn>
    </PropertyGroup>
</Project>