Hot to add an item to a combo box from a textbox?

[CCDriver]

Hi All

How do i add an item from a textbox on one form to a combobox on another form?
I thought you called the form name at the start like this:
frmMain.cboCombo1.AddItem (TextToAdd$)
but this doesn't work, can someone help please.

I need to do this when i click the Ok button and close the form. There are four other textbox's on the form as well which need the items in them to be placed in the corresponding textbox's on the frmMain form.