IIf

Description

The function evaluates condition as a Boolean. If the result is TRUE, it returns the value of Evaluate(string_expression1); otherwise, it returns the value of Evaluate(string_expression2).

Before using IIf, read the Usage section and Note. IIf is primarily intended for the conditional processing of dynamic expressions.

For general conditional processing, see cfif cfelseif cfelse. For error handling, see cftry cfcatch.

Syntax


IIf(condition, string_expression1, string_expression2)

Parameters

Parameter

Description

condition
An expression that can be evaluated as a Boolean

string_expression1
String expression to evaluate and return if condition is TRUE

string_expression2
String expression to evaluate and return if condition is FALSE

Parameter	Description
condition	An expression that can be evaluated as a Boolean
string_expression1	String expression to evaluate and return if condition is TRUE
string_expression2	String expression to evaluate and return if condition is FALSE

Usage

The IIf function is a shortcut for the following construct:

<cfif condition>

  <cfset result = Evaluate(string_expression1)>

<cfelse>

  <cfset result = Evaluate(string_expression2)>

</cfif>

returning result. The expressions string_expression1 and string_expression2 must be string expressions, so that they are not evaluated immediately as the arguments of IIf. For example:

IIf(y is 0, DE("Error"), x/y)

generates an error if y = 0, because the third argument is the value of x/0 (invalid expression).

Recall that ColdFusion evaluates string_expression1 and string_expression2. To return the string itself, use the DE (Delay Evaluation) (delay evaluation) function.

Note

If you use pound signs (#) in string_expression1 or string_expression2, ColdFusion evaluates the part of the expression in pound signs first. By misusing pound signs, you can skew the results of the IIf function. In particular, if you use pound signs around the whole expression in string_expression1, it can cause the function to fail with the error 'Error Resolving Parameter' if there is an undefined variable in string_expression1.

For example, LocalVar is undefined; however, the following logic functions as you would expect if you do not use pound signs around LocalVal:

<cfoutput>

  #IIf(IsDefined("LocalVar"), "LocalVar", DE("The variable is not

    defined."))#

</cfoutput>

The output is:

  The variable is not defined.

Whereas, the pound signs around LocalVar in the following code cause it to fail with the error message 'Error Resolving Parameter', because ColdFusion never evaluates the original condition IsDefined("LocalVar").

<cfoutput>

  #IIf(IsDefined("LocalVar"), DE("#LocalVar#"), DE("The variable 

    is not defined."))#

</cfoutput>

The error message would be:

  Error resolving parameter LOCALVAR

The DE function has no impact on the evaluation of LocalVal, since the pound signs cause it to be evaluated immediately.

Example

<!--- This example shows IIf --->

<html>

<head>

<title>IIf Example</title>

</head>

<body bgcolor = silver>

<H3>IIf Function</H3>

<P>IIf evaluates a condition, and does an Evaluate on string 

expression 1 or string expression 2 depending on the Boolean 

outcome <I>(TRUE: run expression 1; FALSE: run expression 2)</I>.

</P>

<P>The result of the expression 

IIf( Hour(Now()) GT 12, 

 DE("It is afternoon or evening"), 

  DE("It is morning"))

is:<BR>

<cfoutput>

#IIf( Hour(Now()) GT 12, 

 DE("It is afternoon or evening"), 

  DE("It is morning"))#

</cfoutput>

</P>

</body>

</html>

IIf

Description

Category

Syntax

See also

Parameters

Usage

Example

CFML Reference
ColdFusion Functions