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cfparam
327
Usage
You can use this tag to make the following tests:
•
To test whether a required variable exists, use this tag with only the
name
attribute. If it does
not exist, ColdFusion MX stops processing the page and returns an error.
•
To test whether a required variable exists, and that it is of the specified type, use this tag with
the
name
and
type
attributes. If the variable does not exist or its value is not of the specified
type, ColdFusion returns an error.
•
To set a default value for the variable, use this tag with the
name
and
default
attributes. If the
variable does not exist, it is created and set to the
default
attribute value. If the variable exists,
processing continues; the value is not changed.
If you specify
variableName
for the
type
attribute, the parameter’s value must be a string that is
in ColdFusion variable name format; that is, starts with a letter, underscore (_), or Unicode
currency symbol, and contains letters, numbers, underscores, periods, and Unicode currency
symbols, only. ColdFusion does not check whether the parameter value corresponds to an existing
ColdFusion variable.
Tip:
To improve performance, avoid using the
cfparam
tag in ColdFusion functions, including in CFC
methods. Instead, place the
cfparam
tags in the body of the CFML pages.
Example
<!--- This example shows how to use CFPARAM to define default values for page
variables. -------->
<cfparam name = "storeTempVar" default = "my default value">
<cfparam name = "tempVar" default = "my default value">
<!--- Check if form.tempVar was passed. --->
<cfif IsDefined("form.tempVar") is "True">
<!--- Check if form.tempVar is not blank. --->
<cfif form.tempVar is not "">
<!--- If not, set tempVar to value of form.tempVar --->
<cfset tempVar = form.tempVar>
</cfif>
</cfif>
<body>
<h3>cfparam Example</h3>
<p>cfparam is used to set default values so that a developer does not have to
check for the existence of a variable using a function like IsDefined.
<p>The default value of our tempVar is
"<cfoutput>#StoreTempVar# </cfoutput>"
<!--- Check if tempVar is still the same as StoreTempVar.
and that tempVar is not blank --->
min
Optional
The minimum valid value; used only for
range
validation.
pattern
Optional
A JavaScript regular expression that the parameter must match;
used only for
regex
or
regular_expression
validation.
Attribute Req/Opt Default
Description
Содержание COLFUSION MX 7-CFML
Страница 1: ...COLDFUSION MX7 CFML Reference...
Страница 20: ...20 Chapter 1 Reserved Words and Variables...
Страница 50: ...50 Chapter 2 ColdFusion Tags cfelse br Searching cfif cfloop cfif...
Страница 101: ...cfdefaultcase 101 cfdefaultcase cfswitch cfoutput Your grade is grade cfoutput...
Страница 115: ...cfdocumentsection 115 cfdocumentsection cfoutput cfdocument...
Страница 311: ...cfNTauthenticate 311 Please Try again H2 cfif cfoutput cfinclude template loginform cfm cfabort cfif cfif cflogin...
Страница 411: ...cftable 411 cftable body html...
Страница 515: ...Chr 515 maxlength 5 p input type Submit name input type RESET cfform...
Страница 605: ...GetEncoding 605 WriteOutput The encoding is theEncoding cfscript cfif...
Страница 629: ...GetProfileString 629 tr td input type Submit name Submit value Submit td td td tr table form...
Страница 655: ...IIf 655 cfoutput IIf Hour Now GTE 12 DE It is afternoon or evening DE It is morning cfoutput b...
Страница 664: ...664 Chapter 3 ColdFusion Functions cfelse h3 Conversion error h3 cfif...
Страница 687: ...IsStruct 687 cfoutput cfquery cfif cfoutput hr Employee Add Complete cfoutput cfcase cfswitch...
Страница 693: ...IsWDDX 693 struct data wddxPacket hr xmp cfoutput packet xmp IsWDDX returns IsWDDX packet br cfoutput...
Страница 751: ...LSDateFormat 751 hr noshade cfoutput cfloop...
Страница 861: ...StructFind 861 cfquery cfif cfoutput hr Employee Add Complete cfoutput cfcase cfswitch...
Страница 869: ...StructIsEmpty 869 cfoutput cfquery cfif cfoutput hr Employee Add Complete cfoutput cfcase cfswitch...
Страница 903: ...Val 903 value Is the beginning numeric name form...
Страница 932: ...932 Chapter 3 ColdFusion Functions...
Страница 944: ...944 Chapter 4 ColdFusion MX Flash Form Style Reference...
Страница 962: ...962 Chapter 5 Application CFC Reference...
Страница 1008: ...1008 Chapter 6 ColdFusion MX Event Gateway Reference cfset retValue Reason reason cfreturn retValue cffunction...
Страница 1054: ...1054 Chapter 6 ColdFusion MX Event Gateway Reference...