Convert javascript code into C#

Basically, don't. It really won't work well.
Javascript ruins on the client in a browser sandbox, and the range of things it can do is pretty much limited to user interaction.
C# runs on the client and does not interact with the user directly (unless you create a Windows app or similar).

Even if you do try to convert it, the tools and frameworks are totally different, and what works well in one language does not work well in a different one using a totally different framework. Imagine trying to get a Truck engine to work in a Mini car and you'll see the problem: you could do it, with some cutting, welding, and a lot of swearing, but what you end up with isn't a usable vehicle.

Use the JS code as a specification for a new C# app instead. It'll be quicker in the long run, and will produce better code in the end.