I am looking of a free library to develop a simple desktop C# application with GIS support. I have checked the following link but it seems most of the solutions are web-based. Any suggestions?
The link you have provided above shows open source projects which are either desktop applications, or web based applications that provide mapping services/searching tools that can be consumed by desktop applications. eg:
- QGIS - Desktop applicaiton
- Geoserver - publishes WMS, which can be consumed by desktop app.
If i understand your question correctly, it sounds like you are looking for a C# plugin which can create a map window inside of another desktop application (eg: An accounting software package) - im actually not sure about a pure C# app, but maybe there are some .NET libraries that you could hook into? Maybe expand your search into that area.
Otherwise, im not sure how compatible C# is with Python libraries, but these would have extensive source that could be used.