how to forbid the Fatal error: Call to a member function?

Question

Possible Duplicate:
Any reason why Mage::registry(‘current_category’) would return NULL?
Reference - What does this error mean in PHP?

Fatal error: Call to a member function getParentCategory() on a non-object in...

the code:

$_category_detail=Mage::registry('current_category');
$id=$_category_detail->getParentCategory()->getId();

now, when the page can't use getParentCategory() i using the following but can't work.

 if( isset(getParentCategory()){
        $id=$_category_detail->getParentCategory()->getId();  
    }

why? thank you

Shoe · Answer 1 · 2012-12-19T08:52:14.003

4

It appears that $_category_detail is not an object. Therefore Mage::registry('current_category') is not returning an object.

It's most likely returning some sort of NULL or false value upon fail. And PHP is making you notice that (NULL)->getParentCategory() is meaningless.

In your particular case it returns NULL because current_category is not set in your registry.

edited Dec 19 '12 at 08:52

answered Dec 19 '12 at 08:42

Shoe

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score 2 · Accepted Answer · answered Dec 19 '12 at 08:43

2

You need to use method_exists() rather than trying to call a non-existent function:

if (method_exists($_category_detail, "getParentCategory"))

answered Dec 19 '12 at 08:43

Amadan

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Doesn't it trigger an error if `$_category_detail` is not a valid object? – Shoe Dec 19 '12 at 08:46
It won't - Just tested it myself... Neither documentation nor test metion or trigger an error ;) Just returns `false` – Hikaru-Shindo Dec 19 '12 at 09:01

score 1 · Answer 3 · answered Dec 19 '12 at 08:43

1

isset() only checks for member variables. Use method_exists().

PHP Manual: http://php.net/manual/de/function.method-exists.php

if (method_exists($_category_detail, 'getParentCategory')) {
    $id = $_category_detail->getParentCategory()->getId()
}

answered Dec 19 '12 at 08:43

Hikaru-Shindo

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how to forbid the Fatal error: Call to a member function?

3 Answers3