Question

可能重复：
Trying to get property of non-object in

我在为joomla 2.5开发自定义组件时遇到了问题。

我通过MVC结构从数据库中提取数据。一切正常，除非查询没有返回任何结果。

我的视图中出现Trying to get property of non-object错误。

有没有我可以预先知道这一点并向用户显示一条消息，表明没有任何结果？

模型部分：

$this->_gallery = array();
            // Load the data
        if (empty( $this->_gallery )) {
            $query = ' SELECT #__gallery.id, user_id, merk, type, name, bouwjaar, vermogen, #__gallery_kleur.kleur, transmissie, #__gallery_benzine.soort AS brandstof, cilinders, motorinhoud, gewicht, link FROM #__gallery LEFT JOIN #__gallery_merk ON #__gallery.merk_id = #__gallery_merk.merk_id LEFT JOIN #__gallery_type ON #__gallery.type_id = #__gallery_type.type_id LEFT JOIN #__gallery_autoinfo ON #__gallery.id = #__gallery_autoinfo.galleryid LEFT JOIN #__gallery_kleur ON #__gallery_autoinfo.kleur = #__gallery_kleur.kleurid LEFT JOIN #__gallery_benzine ON #__gallery_autoinfo.brandstof = #__gallery_benzine.benzineid LEFT JOIN #__users ON #__gallery.user_id = #__users.id LEFT JOIN (SELECT * FROM #__gallery_foto ORDER BY #__gallery_foto.hoofdfoto ASC) as #__gallery_foto ON #__gallery.id = #__gallery_foto.galleryid GROUP BY #__gallery.id ';
            $this->_db->setQuery( $query );
            $this->_db->query();
            $num_rows = $this->_db->getNumRows();

            $this->_gallery = $this->_db->loadObjectList();
        }
        if (!$this->_gallery) {
            $this->_gallery = new stdClass();
            $this->_gallery->id = 0;
        }
    $this->_total = count($this->_gallery); 

    if ($num_rows == 0) {
    if ($this->getState('limit') > 0) {
 $this->_gallery    = array_splice($this->_gallery, $this->getState('limitstart'), $this->getState('limit') );
    }
    }
     return $this->_gallery;

查看：

    // No direct access to this file
defined('_JEXEC') or die('Restricted access');

// import Joomla view library
jimport('joomla.application.component.view');
jimport( 'joomla.html.pagination' );

/**
 * HTML View class for the HelloWorld Component
 */
class GalleryViewGallery extends JView
{
    // Overwriting JView display method
    function display($tpl = null) 
    {
        $gallery = $this->get( 'Gallery' );
        $this->assignRef( 'gallery',    $gallery );

        $this->items = $this->get('Gallery');
        $this->pagination = $this->get('Pagination'); 

        // Check for errors.
        if (count($errors = $this->get('Errors'))) 
        {
            JError::raiseError(500, implode('<br />', $errors));
            return false;
        }
        // Display the view
        parent::display($tpl);
    }
}

如default.php：

// No direct access to this file
defined('_JEXEC') or die('Restricted access');
//$document = &JFactory::getDocument(); $document->addStyleSheet('components'.DS.'com_gallery'.DS.'css'.DS.'gallery.css');
$document = &JFactory::getDocument(); $document->addStyleSheet('components/com_gallery/css/gallery.css');
?>
<p>
In onderstaande overzicht wordt overzicht van galleries getoond, ben op je zoek naar iets specifieks ?. Gebruik dan het zoekscherm aan de linkerkant van deze pagina om een aangepast overzicht te tonen.
</p>
<?php
$count = '1';

foreach($this->gallery as $gallery){
if($count == '0'){
    echo 'Geen resultaat';
}else{
?>
<div class="gallery_wrapper">
<?php
if($gallery->merk OR $gallery->type > Null){
echo "<div class=\"gallery_merktype\">";
echo "<a href='gallerie?view=gallerydetail&amp;gallery=" . $gallery->id . "' target='_self'>";
echo "<H1>";
echo $gallery->merk;
echo " ";
echo $gallery->type;
echo "</H1>";
echo "</a>";
echo "</div>";
}
//Weergeven afbeelding, bepaling maximale hoogte en breedte gebeurt in CSS.
if($gallery->link > Null){
echo "<div class=\"gallery_foto\">";
echo "<div class=\"gallery_foto_clip\">";
echo "<a href='gallerie?view=gallerydetail&amp;gallery=" . $gallery->id . "' target='_self'><img src='../galleryimage/thumb/" . $gallery->link . "' width='200px' alt='Afbeelding'/></a>";
echo "</div></div>";
}               
?>
<div class="gallery_wrapper_info">
<?php
//Weergeven gallery gegevens.
if($gallery->bouwjaar > Null){
echo "<div class=\"gallery_info_title\">Bouwjaar:</div>";
echo "<div class=\"gallery_info_values\">";
echo $gallery->bouwjaar;
echo "</div>";
}
if($gallery->vermogen > Null){
echo "<div class=\"gallery_info_title\">Vermogen:</div>";
echo "<div class=\"gallery_info_values\">";
echo $gallery->vermogen;
echo "</div>";
}
if($gallery->kleur > Null){
echo "<div class=\"gallery_info_title\">Kleur:</div>";
echo "<div class=\"gallery_info_values\">";
echo $gallery->kleur;
echo "</div>";
}
if($gallery->transmissie > Null){
echo "<div class=\"gallery_info_title\">Transmissie:</div>";
echo "<div class=\"gallery_info_values\">";
echo $gallery->transmissie;
echo "</div>";
}
if($gallery->brandstof > Null){
echo "<div class=\"gallery_info_title\">Brandstof:</div>";
echo "<div class=\"gallery_info_values\">";
echo $gallery->brandstof;
echo "</div>";
}               
if($gallery->cilinders > Null){
echo "<div class=\"gallery_info_title\">Cilinders:</div>";
echo "<div class=\"gallery_info_values\">";
echo $gallery->cilinders;
echo "</div>";
}
if($gallery->motorinhoud > Null){
echo "<div class=\"gallery_info_title\">Motorinhoud:</div>";
echo "<div class=\"gallery_info_values\">";
echo $gallery->motorinhoud;
echo "</div>";
}
if($gallery->gewicht > Null){
echo "<div class=\"gallery_info_title\">Gewicht:</div>";
echo "<div class=\"gallery_info_values\">";
echo $gallery->gewicht;
echo "</div>";
}
?>
<div class="gallery_bekijken">
<H2><a href="index.php/gallerie?view=gallerydetail&amp;gallery=<?php echo $gallery->id; ?>" target="_self">Bekijk Gallery</a></H2>
</div>
</div>

</div>


<?php   
}
}
?>

<form method="post" name="limiet">
<?php echo $this->pagination->getPagesLinks(); ?>
<center>
<?php echo $this->pagination->getLimitbox(); ?>
</center>
</form>

太棒了！，我已经尝试过以下方式了，它对我有用：

if(is_object($this->gallery)){
echo "No result";
}else{

//DATA

}

记录：

填充数组的print_r：

Array ( [0] => stdClass Object ( [id] => 146 [user_id] => 861 [merk] => Seat [type] => Leon [name] => Danny [bouwjaar] => 2004 [vermogen] => 190 [kleur] => Geel [transmissie] => Handgeschakeld [brandstof] => Diesel [cilinders] => 4 [motorinhoud] => 1900 [gewicht] => 1210 [link] => p1793sjnq51u373r12qdobs1d2b2.jpg ) )

一个空的：

stdClass Object ( [id] => 0 )

虽然我之前遗漏了一些内容，但在模型中我将限制变量调整为'0'而不是默认的'5'进行测试。

如果我把它放回'5'，当查询没有返回任何结果时，我得到一个array_splice错误。当有数据时，它可以很好地工作。

也许我在这里做错了什么？

我的模型中的代码片段：

$this->_gallery = array();
            // Load the data
        if (empty( $this->_gallery )) {
            $query = ' SELECT #__gallery.id, user_id, merk, type, name, bouwjaar, vermogen, #__gallery_kleur.kleur, transmissie, #__gallery_benzine.soort AS brandstof, cilinders, motorinhoud, gewicht, link FROM #__gallery LEFT JOIN #__gallery_merk ON #__gallery.merk_id = #__gallery_merk.merk_id LEFT JOIN #__gallery_type ON #__gallery.type_id = #__gallery_type.type_id LEFT JOIN #__gallery_autoinfo ON #__gallery.id = #__gallery_autoinfo.galleryid LEFT JOIN #__gallery_kleur ON #__gallery_autoinfo.kleur = #__gallery_kleur.kleurid LEFT JOIN #__gallery_benzine ON #__gallery_autoinfo.brandstof = #__gallery_benzine.benzineid LEFT JOIN #__users ON #__gallery.user_id = #__users.id LEFT JOIN (SELECT * FROM #__gallery_foto ORDER BY #__gallery_foto.hoofdfoto ASC) as #__gallery_foto ON #__gallery.id = #__gallery_foto.galleryid GROUP BY #__gallery.id ';
            $this->_db->setQuery( $query );
            $this->_gallery = $this->_db->loadObjectList();
        }
        if (!$this->_gallery) {
            $this->_gallery = new stdClass();
            $this->_gallery->id = 0;
        }
    $this->_total = count($this->_gallery); 

    if ($this->getState('limit') > 0) {
     $this->_gallery    = array_splice($this->_gallery, $this->getState('limitstart'), $this->getState('limit') );
    }
     return $this->_gallery;
}

当没有结果且限制设置为5时，我的视图中出现错误：

Warning: array_splice() expects parameter 1 to be array, object given in

Print_R没有回馈结果，但这显然是我的问题。

Answer 1

检查对象是否有数据。您可以使用以下

的组合

isset- Determine if a variable is set and is not NULL

is_null - Finds whether a variable is NULL

empty — Determine whether a variable is empty

is_array — Finds whether a variable is an array 

is_object — Finds whether a variable is an object

您可以使用类似的内容（如果行数为0，则将对象设置为null）。

If(!is_null($this->gallery))
{
//show data
}
else
{
//show a msg
}

您只需检查$this->gallery是否为对象。

If(is_object($this->gallery))
{
//show data
}
else
{
//show a msg
}

根据结果集明智地选择上述内容。如果您可以发布print_r我可以准确地告诉您必须使用的内容。

有关问题的更新

警告：array_splice（）期望参数1是数组，给定对象在

它可能无效的原因是因为$this->_gallery可能不是数组。

stdClass Object（[id] =＆gt; 0）＆lt; - 这是一个不是数组的对象。如果你要调用array_slice（）函数，第一个参数应该是一个数组。

要检查某些内容是否为数组，您可以执行以下操作：

is_array($this->_gallery); // returns true or false

如果是数组，则可以调用array_slice()。

希望这会有所帮助。如果您有任何问题，请在此处询问。

Joomla 2.5试图获取非对象错误的属性

1 个答案: