[pmorici]

"Use VB.NET or Delphi for the front-end user interface."

Or, you could use something that's cross platform like Python.

[jodrellblank]

Using which Pythonic stable, tested, documented drag-n-drop GUI/RAD toolkit?

[pmorici]

There are a lot. the built-in TK library has worked well for me in the past. It supports some drag and drop.