如何在TYPO3 Fluid中显示整数0但不为空或NULL

Question

In my TYPO3 Fluid template I have a value where I would like to check if its not empty before showing it. My way now:

<f:if condition="{myvalue}">
<div class="myclass">{myvalue}</div>
</f:if>

This works when I type in the backend a value like "test" or "2", and if I dont type anything it won't show the div tag. But when I type in the backend "0", the condition is also not true. How can I fix that the integer 0 will be showed, and if its empty (in database NULL) not be showed? (its very common that the value will be 0)

Btw i tried things like:

<f:if condition="{myvalue} !=NULL">
<f:if condition="{myvalue} >= 0">

But then also the empty value's wil be show. If I do

<f:debug>{myvalue}</f:debug>

I get things like:

myvalue = NULL 
myvalue = 0 
myvalue = "test"

So only the first one must not been shown.

I hope someone can help me, thank you.

Answer 1

There are two solutions first is transient field in your model of bool type which getter just checks if value is not null, but additionally returns true if value is 0 (actually in most languages 0 IS a value)

Second solution is even more universal, it's just writing custom ViewHelper, which will allow uou to check if value is 0 or has value:

<?php
namespace VENDOR\YourExt\ViewHelpers;

class notEmptyOrIsZeroViewHelper extends \TYPO3\CMS\Fluid\Core\ViewHelper\AbstractViewHelper {

    /**
     * @param mixed $value Value to check
     *
     * @return bool the rendered string
     */
    public function render($value) {
        return ($value === 0 || $value === '0' || $value) ? true : false;
    }
}

So you can later use this as a condition for common <f:if > condition like:

<f:if condition="{yourNameSpace:notEmptyOrIsZero(value: myValue)}">
    <f:then>Now it recognizes 0 as a value</f:then>
    <f:else>It still DOESN'T recognize 0 as a value</f:else>
</f:if>

Answer 2

I had a similar case, where I wanted to check a fluid variable for 0 or positive integers. A simple >= 0 comparison wouldn't work. In TYPO3 10 LTS I could resolve this problem by doing this:

<f:if condition="{value} === 0 || {value * 1} > 0">
    value is zero or positive integer
</f:if>

(Note: this will also allow integer strings, such as "123" or "1st", but not "val3" - basically as you would expect when casting a string as integer in PHP.)

If you just want to check that {value} is not null or empty (but allow zero as a valid value), you can simplify the condition to:

<f:if condition="{value} === 0 || {value}">
    value is set and not empty
</f:if>