if ViewHelper <f:if>

This ViewHelper implements an if/else condition.

Conditions:

As a condition is a boolean value, you can just use a boolean argument. Alternatively, you can write a boolean expression there. Boolean expressions have the following form:

XX Comparator YY

Comparator is one of: ==, !=, <, <=, >, >= and % The % operator converts the result of the % operation to boolean.

XX and YY can be one of:

  • number
  • Object Accessor
  • Array
  • a ViewHelper
  • string
<f:if condition="{rank} > 100">
    Will be shown if rank is > 100
</f:if>
<f:if condition="{rank} % 2">
    Will be shown if rank % 2 != 0.
</f:if>
<f:if condition="{rank} == {k:bar()}">
    Checks if rank is equal to the result of the ViewHelper "k:bar"
</f:if>
<f:if condition="{foo.bar} == 'stringToCompare'">
    Will result in true if {foo.bar}'s represented value equals 'stringToCompare'.
</f:if>
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Examples

Basic usage

<f:if condition="somecondition">
    This is being shown in case the condition matches
</f:if>
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Output:

Everything inside the <f:if> tag is being displayed if the condition evaluates to TRUE.
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If / then / else

<f:if condition="somecondition">
    <f:then>
        This is being shown in case the condition matches.
    </f:then>
    <f:else>
        This is being displayed in case the condition evaluates to FALSE.
    </f:else>
</f:if>
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Output:

Everything inside the "then" tag is displayed if the condition evaluates to TRUE.
Otherwise, everything inside the "else"-tag is displayed.
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inline notation

{f:if(condition: someCondition, then: 'condition is met', else: 'condition is not met')}
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Output:

The value of the "then" attribute is displayed if the condition evaluates to TRUE.
Otherwise, everything the value of the "else"-attribute is displayed.

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Arguments

then

DataType
mixed
Required
false
Description
Value to be returned if the condition if met.

else

DataType
mixed
Required
false
Description
Value to be returned if the condition if not met.

condition

DataType
boolean
Required
false
Description
Condition expression conforming to Fluid boolean rules