Override CStatic to give you an MFC class that subclasses the picture box.
Add an OnPaint handler to that new class.
In the OnPaint handler, get a DC with BeginPaint
Use MoveTo[^] and LineTo[^] to draw a line
Add a class variable (of the type you created in step 1) for the picture box in your parent window
drawline on picture box - DONE!
Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p