MACROMEDIA COLDFUSION MX 61-DEVELOPING COLDFUSION MX Applications - page 576
576
Chapter 26: Retrieving and Formatting Data
Creating dynamic check boxes and multiple-selection
list boxes
When an HTML form contains either a list of check boxes with the same name or a multiple-
selection list box (that is, where users can select multiple items from the list), the user's entries are
made available as a comma-delimited list with the selected values. These lists can be very useful
for a wide range of inputs.
Note: If the user does not select a check box or make a selection from a list box, no variable is
created. The
cfinsert
and
cfupdate
tags do not work correctly if there are no values. To correct
this problem, make the form fields required, use Dynamic SQL, or use
cfparam
to establish a default
value for the form field.
Check boxes
When you put a series of check boxes with the same name in an HTML form, the variable that is
created contains a comma-delimited list of values. The values can be either numeric values or
alphanumeric strings. These two types of values are treated slightly differently.
Handling numeric values
Suppose you want a user to select one or more departments using check boxes. You then query the
database to retrieve detailed information on the selected department(s). The code for a simple set
of check boxes that lets the user select departments looks like the following:
name="SelectedDepts"
value="1">
Training
name="SelectedDepts"
value="2">
Marketing
name="SelectedDepts"
value="3">
HR
name="SelectedDepts"
value="4">
Sales