MACROMEDIA ColdFusion MX, Develop Manual, Page: 238 / 860

238 Chapter 11: Building and Using ColdFusion Components
Defining and using method parameters
To define the component method parameter, use the
cfargument
tag in the
cffunction
tag
body. To define multiple parameters, use multiple
cfargument
tags. You can create CFC methods
that do not use
cfargument
tags, for example, if you use positional parameters in your methods.
However, most CFC methods use the
cfargument
tag. The tag names a parameter and lets you
specify the following:
•
Whether the parameter is required
•
The type of data that is required
•
A default argument value
•
Display name and hint metadata for CFC introspection
For detailed reference information on the
cfargument
tag, see CFML Reference .
To access the parameter values in the component method definition, use structure- or array-like
notation with the Arguments scope. The following example refers to the lastName argument as
Arguments.lastName; it could also refer to it as Arguments[1]. In addition, you can access
arguments directly using pound signs, such as #lastName#; however, it is better programming
practice to identify the scope. Also, you can use Array- or structure-like notation, which lets you
loop over multiple parameters.
For more information on the Arguments scope, see “The Arguments scope” on page 243 .
Note: For the following procedure to work, you must have the example applications installed with
ColdFusion MX. For more information, see CFML Reference .
To define parameters in the component method definition:
•
Create a new component with the following contents, and save it as corpQuery.cfc in a
directory under your web root directory.
<cfcomponent>
<cffunction name="getEmp">
<cfargument name="lastName" type="string" required="true"
hint="Employee last name">
<cfquery name="empQuery" datasource="ExampleApps" dbtype="ODBC">
SELECT LASTNAME, FIRSTNAME, EMAIL
FROM
tblEmployees
WHERE LASTNAME LIKE '#Arguments.lastName#'
</cfquery>
<cfoutput>Results filtered by #Arguments.lastName#:</cfoutput><br>
<cfdump var=#empQuery#>
</cffunction>
<cffunction name="getCat" hint="Get items below specified cost">
<cfargument name="cost" type="numeric" required="true">
<cfquery name="catQuery" datasource="ExampleApps" dbtype="ODBC">
SELECT ItemName, ItemDescription, ItemCost
FROM
tblItems
WHERE ItemCost <= #Arguments.cost#
</cfquery>
<cfoutput>Results filtered by #Arguments.cost#:</cfoutput><br>
<cfdump var=#catQuery#>
</cffunction>
</cfcomponent>