Programming ColdFusion MX, 2nd Edition

Creating Components

Creating a CFC is easy. You simply define the component using the cfcomponent tag and save the file with a .cfc extension. cfcomponent is a paired tag that acts as a container for the CFC. Within the component, you can have any number of properties (defined by the cfproperty tag) and methods (each defined using a pair of cffunction tags). Each method can accept zero or more arguments, defined with cfargument tags. If a CFC returns any data, it does so with the cfreturn tag. Essentially, a component is a collection of related UDFs grouped within a cfcomponent container. Syntactically, a basic CFC looks like this:

<cfcomponent>
  <cfproperty />
  
  constructor code...
   
  <cffunction>
    <cfargument>
    CFML
    <cfreturn>
  </cffunction>
   
  <cffunction>
    <cfargument>
    CFML
    <cfreturn>
  </cffunction>
</cfcomponet>

The cfcomponent tag has four optional attributes:

displayname=" display_name "

Used to display a descriptive name for the component in ColdFusion MX’s Component Browser or when the component is introspected using the getMetaData( ) function. These concepts are discussed later in the chapter.

hint=" text "

Used to display a hint describing what the component does in ColdFusion MX’s Component Browser or when the component is introspected using the getMetaData( ) function.

extends=" component_name "

Name of a parent component from which the component should inherit methods and properties.

output="yes|no"

Indicates whether the component’s constructor code (any area within the