Simple web solution, similar to Apache Jena Fuseki, you can upload your file(OWL) to use the query.
You can upload your private Owl Files.
An Open Source .NET Library for RDF
complete library for parsing, managing, querying and writing RDF.
common .NET API for working with RDF triple stores such as AllegroGraph, Jena, Stardog and Virtuoso.
Query for more file types (ttl, etc.)