Visual Assist is compatible with JetBrains ReSharper for C#. Visual Assist provides assistance when editing C/C++, and both extensions assist when editing C#.
If you wish Visual Assist to display completion listboxes and parameter info in C#, configure ReSharper options to use the IntelliSense from Visual Studio.
If you want to use Visual Assist for C/C++ and ReSharper for C#, tell Visual Assist to ignore extensions associated with C# in the options dialog for Visual Assist. If you have a C# window open, reopen the window after updating the options dialog.