And you only need the code if you're actually _storing_ the extra column from the combo box. If you're just displaying it, set the control source of the text box = ComboName.Column(x) (for some reason, you have to leave off the Me. part).
Actually having store the extra column is relatively rare, and should only be done when you cannot rely on being able to go back to it later and it having the same value. Price information is a good example of this.