C # to write the C/S projects to B/S technology selection advice,

Project background: the.net C # to write the C/S, C and S end use SOCKET communication, developers to C + +, C # more skilled,

Modify requirements:
1, S side does not change, add a WebService or WCF service, used for the front-end and back-end (S) communication, both maintained the "C/S application" before, still can continue to use the
2, B side (WEB front-end) using the Bootstrap design WEB UI page (new learning the Bootstrap, really efficient and beautiful),

The concrete implementation:
WEB front-end after how to invoke the WEB service or WCF service will display the back-end data into a WEB front-end UI interface?

Some doubt:
1, B side (WEB front-end) : to understand the ASP.NET data, most of them speak of WEB FORM,
2, many people clearly suggest that we do not use the WEB FORM developing WEB front end,
3, also don't use ASP.NET framework, it is suggested that WEB front-end directly using the Vue. Js, the Bootstrap,
Have 4, to understand the.net core, feel this could be the later. The trend of net, our side a and B and S (WEB front-end) application should correct it can be used, can be cross-platform, but now can't change the backend server program c #, just add a layer of WebService or WCF service for WEB and WEB front-end, temporarily don't want to use. Net core to do,
5, use JAVA to do WEB front-end, need to spend much more time,

Have made similar enterprise application? Beg god give directions, thank you,