
Dynamic expressions and dynamic variables
99
<cfif i mod 2 EQ 0>
<cfset Color = "white">
<cfelse>
<cfset Color = "gray">
</cfif>
<tr bgcolor="#color#">
<td>
hello #i#
</td>
</tr>
</cfloop>
</table>
</cfoutput>
Example: a dynamic shopping cart
The following example dynamically creates and manipulates variable names without using
dynamic expression evaluation by using associative array notation.
You need to dynamically generate variable names in applications such as shopping carts, where
the required output is dynamically generated and variable. In a shopping cart, you do not know in
advance the number of cart entries or their contents. Also, because you are using a form, the
action page only receives Form variables with the names and values of the form fields.
The following example shows the shopping cart contents and lets you edit your order and submit
it. To simplify things, the example automatically generates the shopping cart contents using
CFScript instead of having the user fill the cart. A more complete example would populate a
shopping cart as the user selected items. Similarly, the example omits all business logic for
committing and making the order.
To create the form:
1
Create a file in your editor.
<html>
<head>
<title>Shopping Cart</title>
</head>
<cfscript>
CartItems=4;
Cart = ArrayNew(1);
for ( i=1; i LE cartItems; i=i+1)
{
Cart[i]=StructNew();
Cart[i].ID=i;
Cart[i].Name="Product " & i;
Cart[i].SKU=i*100+(2*i*10)+(3*i);
Cart[i].Qty=3*i-2;
}
</cfscript>
<body>
Your shopping cart has the following items.<br>
You can change your order quantities.<br>
If you don't want any item, clear the item's check box.<br>
When you are ready to order, click submit.<br>
<br>
<cfform name="ShoppingCart" action="ShoppingCartAction.cfm" method="post">
<table>
<tr>
Содержание COLDFUSION MX 61-DEVELOPING 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...