Your best best shot for code completion is to use ASP.NET Core Tag Helpers
http://www.jqwidgets.com/jquery-widgets-documentation/documentation/asp-net-core/mvc-tag-helpers.htm?search=
If you starting from scratch you may take look at ASP.NET Core MVC platform
There is free IDE VS Communtiy Edition
When you wireup jqwidgets Core Tag Helpers inside MVC project you get intellisense in RAZOR.
@admin
I hope that is ok from my side to answer after you.
When we already speaking about .NET Core Tag Helpers.
Does jqwidgets is going to be developed and maintained for .NET Core Tag Helpers.
Only one reason for me to switch over .NET 4.6 to .NET Core is your helpers.
But If there is no hope for future about helpers then I will wait for better times.
I see that there is release jQWidgets v4.4.0 Release, November-24-2016 but unfortunately no any progress about .NET Core Tag Helpers
Thanx in advanced