Custom build version number in dotnet

project.csproj

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Target Name="BeforeBuild">
    <!-- https://stackoverflow.com/a/6472195/2076784 -->
    <PropertyGroup>
      <Year>$([System.DateTime]::Now.ToString("yyyy"))</Year>
      <Month>$([System.DateTime]::Now.ToString("MM"))</Month>
      <Date>$([System.DateTime]::Now.ToString("dd"))</Date>
      <Time>$([System.DateTime]::Now.ToString("HHmm"))</Time>
      <AssemblyFileVersionAttribute>[assembly:System.Reflection.AssemblyFileVersion("$(Year).$(Month).$(Date).$(Time)")]</AssemblyFileVersionAttribute>
    </PropertyGroup>
    <WriteLinesToFile File="Properties\VersionInfo.cs" Lines="$(AssemblyFileVersionAttribute)" Overwrite="true">
    </WriteLinesToFile>
  </Target>
</Project>