WiX v4 is based around NuGet. That means the same techniques for taking NuGet packages offline will work for WiX v4. Here are some example steps that could get you started.
- Download the WixToolset.Sdk from NuGet.org. See the download link on the right of the page at: https://www.nuget.org/packages/WixToolset.Sdk
- Place the WixToolset.Sdk in a folder. For example X:\saved\nupkgs\
- Create a nuget.config file to point at that folder. For example
<?xml version="1.0" encoding="utf-8"?>
<add key="local" value="X:\saved\nupkgs" />
- Create a Test.wixproj in the same folder. For example
- Verify it works by running: "msbuild -Restore"
The build will fail because there are no .wxs files to compile so there is no output, but when the restore works, you know you are using the local folder.