Programming ColdFusion MX, 2nd Edition

Conditional Processing

Conditional processing makes it possible to implement flow control and decision making within your ColdFusion templates. ColdFusion provides three techniques for applying conditional processing in your programs: if/elseif/else functionality with the <cfif>, <cfelseif>, and <cfelse> tags; a C-style switch statement with the <cfswitch>, <cfcase>, and <cfdefaultcase> tags; and the IIF( ) function for inline conditionals.

cfif, cfelseif, and cfelse

If/elseif/else processing allows you to add logical decision-making and flow control to your ColdFusion applications, so you can evaluate an expression and take different actions based upon the results. Basic if/elseif/else processing takes the following form:

<cfif expression>
   HTML and CFML...
<cfelseif expression>
   HTML and CFML...
<cfelse>
   HTML and CFML...
</cfif>

The cfif statement can evaluate any expression capable of returning a Boolean value. If the statement evaluates true, ColdFusion processes the code associated with the cfif statement. The cfelseif statement provides an alternate expression in the event that the expression in the cfif statement evaluates false. Any number of cfelseif statements can provide additional decision-making options. The cfelse statement provides a default option in the event that both the cfif statement and any cfelseif statements all evaluate false. The following example uses if/elseif/else logic to evaluate a URL variable called Action:

<cfif URL.Action IS "Add"> <cfinclude ...