c# ajax json web api mvc

Do you want to get the data in your Web API from an AJAX call? If so, then there are tons of example for that. Here's one example: https://www.codeproject.com/Articles/424461/Implementing-Consuming-ASP-NET-WEB-API-from-JQuery

 

I would suggest you to learn how Web API, AJAX and JSON serialization works first so that you will know how you connect these pieces together.