Adding files generated at build time to your ClickOnce deployment

So, it used to be that I didn't really like ClickOnce deployment, but it turns out it has a lot of benefits:

• It provides infrastructure that makes it *exceedingly* easy for your average lay-user to upgrade. All they have to do is start the program as normal, and it automatically updates for them (when configured properly)
• It bundles everything up nicely and is easy to install and uninstall (if you're a real person. If you're a script, not so much)

I recently encountered the problem of including files generated at build time (e.g. transformed configuration files) in the ClickOnce deployment package. I found the following that I could include in my ClickOnce project's .csproj MSBuild file:

 <Content Include="Path\To\My.file" Condition=" Exists('Path\To\My.file') ">
<Visible>false</Visible>
 </Content>

 The key part to getting it to work properly is that your build has to do a Build target first, then a Publish target (usually with two separate invocations of MSBuild via a build script, rather than building with a Solution). Fortunately, I was already set up for that, so getting the extra files included was a dream.