I want to create a Context menu in circle shape that consist of 8 pieces just like Pizza slice
for reference : software 'bumpTop' also have same kind of menu.
Can any one tell me ,How to make this type of customize context menu in c# or visual basic like we make default shape ContextMenuStrip in C#.

You can create a custom form (call it when right click).
Search google how to make custom chapes of forms.
Here is an exampe. Put some buttons on it (or some other controls) which will be made for choosing options.