If you have created a control using the Control Toolbox and you would like the information in this control to be saved with the form, the control must be bound to a field. This means that a link will be established between the control and the source of data, in this case, a field in the item.
Note If you bind a ListBox, ComboBox, OptionButton, or CheckBox to a field, then the Click event does not fire. You need to use the PropertyChange or CustomPropertyChange event to detect the change via code.
Example:
Sub Item_PropertyChange(ByVal Name)
Set MyListBox = Item.GetInspector.ModifiedFormPages("Message").Controls("ListBox1")
Select Case Name
Case "Mileage"
Item.CC = MyListBox.Value
Item.Subject = MyListBox.Value
Case Else
End Select
End Sub