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 ...