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:
<input type="checkbox"
name="SelectedDepts"
value="1">
Training<br>
<input type="checkbox"
name="SelectedDepts"
value="2">
Marketing<br>
<input type="checkbox"
name="SelectedDepts"
value="3">
HR<br>
<input type="checkbox"
name="SelectedDepts"
value="4">
Sales<br>
</html>
The user sees the name of the department, but the
value
attribute of each check box is a number
that corresponds to the underlying database primary key for the department's record.
If the user checks the Marketing and Sales items, the value of the SelectedDepts form field is
"2,4" and you use the SelectedDepts in the following SQL statement:
SELECT *
FROM Departmt
WHERE Dept_ID IN ( #Form.SelectedDepts# )
Содержание ColdFusion MX
Страница 1: ...Developing ColdFusion MX Applications...
Страница 22: ...22 Contents...
Страница 38: ......
Страница 52: ...52 Chapter 2 Elements of CFML...
Страница 162: ......
Страница 218: ...218 Chapter 10 Writing and Calling User Defined Functions...
Страница 250: ...250 Chapter 11 Building and Using ColdFusion Components...
Страница 264: ...264 Chapter 12 Building Custom CFXAPI Tags...
Страница 266: ......
Страница 314: ...314 Chapter 14 Handling Errors...
Страница 344: ...344 Chapter 15 Using Persistent Data and Locking...
Страница 349: ...About user security 349...
Страница 357: ...Security scenarios 357...
Страница 370: ...370 Chapter 16 Securing Applications...
Страница 388: ...388 Chapter 17 Developing Globalized Applications...
Страница 408: ...408 Chapter 18 Debugging and Troubleshooting Applications...
Страница 410: ......
Страница 426: ...426 Chapter 19 Introduction to Databases and SQL...
Страница 476: ...476 Chapter 22 Using Query of Queries...
Страница 534: ...534 Chapter 24 Building a Search Interface...
Страница 556: ...556 Chapter 25 Using Verity Search Expressions...
Страница 558: ......
Страница 582: ...582 Chapter 26 Retrieving and Formatting Data...
Страница 668: ......
Страница 734: ...734 Chapter 32 Using Web Services...
Страница 760: ...760 Chapter 33 Integrating J2EE and Java Elements in CFML Applications...
Страница 786: ...786 Chapter 34 Integrating COM and CORBA Objects in CFML Applications...
Страница 788: ......
Страница 806: ...806 Chapter 35 Sending and Receiving E Mail...