如何获取将发布到web api的多个json对象列表的名称数据？

I have a post method in Web API ASP.NET that accepts a single Json object. Here is the code with a code to check if data from the posting Json is existing in my database. and I will be using Linq to interact with my DB. Sales_ was auto-generated in my context, I believe from EntityFramework. db is my database object.I have a post method in Web API ASP.NET that ac