One of the visitors to my site did a search for "c# googledesktop". Whilst I have never done any plugin programming for the Google Desktop, there is an article that exists called "Improving Search Precision Using Goolgle Desktop Search 1.0" this article was in the November 2005 Doctor Dobb's Journal.It covers a C# implemenation for searching the Citeseer database with some extra information using Google Desktop. It is a nice article to read and it even mentions some of the changes required to get it working in Google Desktop 2.0.www.ddj.com is the website, not too sure you can access the article unless you are a subscriber though.
About Me: Paul Kinlan
I lead the Chrome Developer Relations team at Google.
We want people to have the best experience possible on the web without having to install a native app or produce content in a walled garden.
Our team tries to make it easier for developers to build on the web by supporting every Chrome release, creating great content to support developers on web.dev, contributing to MDN, helping to improve browser compatibility, and some of the best developer tools like Lighthouse, Workbox, Squoosh to name just a few.