An example Visual Studio pubxml file to zip the output when publishing an ASP.NET web application to file system

Example.pubxml

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <WebPublishMethod>FileSystem</WebPublishMethod>
    <LastUsedBuildConfiguration>Debug</LastUsedBuildConfiguration>
    <LastUsedPlatform>Any CPU</LastUsedPlatform>
    <SiteUrlToLaunchAfterPublish />
    <LaunchSiteAfterPublish>True</LaunchSiteAfterPublish>
    <ExcludeApp_Data>False</ExcludeApp_Data>
    <publishUrl>C:\Publish\SimpleExample</publishUrl>
    <DeleteExistingFiles>True</DeleteExistingFiles>    
  </PropertyGroup>
  <Target Name="ZipPublishOutput" AfterTargets="GatherAllFilesToPublish">
    <Exec Command='powershell -nologo -noprofile -command "compress-archive -force -path $(WPPAllFilesInSingleFolder)\* -destinationpath $(publishUrl).zip"' />
  </Target>
</Project>

For anyone using VS 2019 or later, you can also leverage the <ZipDirectory> task:

  <Target Name="ZipPublishOutput" AfterTargets="FileSystemPublish">
    <ZipDirectory SourceDirectory="$(publishUrl)" DestinationFile="$(publishUrl)\..\$(MSBuildProjectName).zip" />
    <RemoveDir Directories="$(publishUrl)" />
  </Target>