I'm developing applications using either WPF or WindowFormApps that can store and manage database. The question is that how can i create an in-app database or which kind of database should I use that can run whenever I install it on other devices. My application cannot run on other devices since there is no SQL server on that PC and the connectionstring is different also.
Have you looked into SQLite? Also, there is a distributable product by SAP "Advantage Database Local Server". The local is for local / stand-alone machine distribution. I'll try to find link. The Advantage Database runs via dlls sitting in the execution folder and has .net support as I too work with it within C#/WPF world and works fine.
Found this page for the download. ADS = Advantage Database SERVER. ALS is Advantage LOCAL server.