How do I close the form in VB?

This paragraph code implements other forms outside of the specified form in VB, which is actually used to close all sub-forms:

code show as below:

'To prevent database connections, you can't close, turn off all windows here.

DIM FRM AS FORM

For Each FRM in Forms

IFfrm.name <> "frmmdimain" THEN Unload FRM

NEXT