How can I add right click functionality(context menu) like show column , add column , and remove column to my ASP.NET gridcontrol?

At least get started by googling "asp.net add context menu" and go from there. This is not a trivial task though. If you're looking to do this kind of work then a gridview might not be the best thing to use, a more client-based table like jgrid or something might be easier to work with. Asp.net server controls are not designed to be manipulated by client javascript.