调用非对象上的成员函数bind_param()，该对象在从另一个函数调用的函数内部不起作用 [英] Call to a member function bind_param() on a non-object not working inside function called from another function

问题描述

我在下面列出的类的get_template()函数中收到上述错误.有谁知道我为什么收到此错误?所有其他查询都可以正常执行，并且$ template_number肯定返回查询中目前期望的int值，为什么我会收到此错误?可能是因为该查询的返回在MySQL中的格式为TEXT(在PHPMyAdmin中显示为BLOB)?

I'm receiving the error above in the get_template() function of my class listed below. Does anyone know why I am receiveing this error? All of the other queries execute fine and $template_number is definitely returning an int which is expected at this point in the query so why am I receiving this error? Could it be because the return on this query is formatted as TEXT in MySQL (and appears as a BLOB in PHPMyAdmin?

    class Page{

private $con; 

public function __construct(Connection $con) {
    $this->con = $con;
    if(isset($_GET['id'])){
    $id = $_GET['id'];
    }else{      
    $id = 1;
    }       
    $this->get_headers($id);
    $this->get_content($id);
    $this->get_footer($id);
}

private function get_headers($pageId){ 
    $retrieveHead = $this->con->prepare("SELECT headers FROM pages WHERE page_id=?");
    $retrieveHead->bind_param('i',$pageId);
    $retrieveHead->execute();
    $retrieveHead->bind_result($header);
    $retrieveHead->fetch();
    $retrieveHead->close();
    echo $header;   
}

private function get_footer($pageId){ 
    $retrieveFooter = $this->con->prepare("SELECT footer FROM pages WHERE page_id=?");
    $retrieveFooter->bind_param('i',$pageId);
    $retrieveFooter->execute();
    $retrieveFooter->bind_result($footer);
    $retrieveFooter->fetch();
    $retrieveFooter->close();
    echo $footer;   
}

private function get_content($pageId){
    $retreiveContent = $this->con->prepare("SELECT template_id, section_title, i1, i2 FROM content WHERE page_id=? ORDER BY sequence DESC");
    $retreiveContent->bind_param('i',$pageId);
    $retreiveContent->execute();
    $retreiveContent->bind_result($template_id, $section_title, $i1, $i2);
         while ($retreiveContent->fetch()) {
            //Variables will be populated for this row.
            //Update the tags in the template.
            $template = $this->get_template($template_id);
            $template = str_replace('[i1]',$i1,$template);
            $template = str_replace('[i2]',$i2,$template);
            //$theTemplate is populated with content. Probably want to echo here
            echo $template;
        }
    $retreiveContent->close();
}

private function get_template($template_number){
    $retreiveFunction = $this->con->prepare("SELECT code FROM templates WHERE template_id=?");
    $retreiveFunction->bind_param('i',$template_number);
    $retreiveFunction->execute();
    $retreiveFunction->bind_result($template);
    $retreiveFunction->fetch();
    $retreiveFunction->close();
    return $template;
}

}

表结构可以在下面找到:

Table structure can be found below:

推荐答案

对于其他正在寻找此解决方案的人，正如bwewsing建议我需要在store_result中添加，但是从上面提供的链接中尚不清楚应该在何处实现.

For anyone else searching for this solution, as bwewsing suggests I needed to add in store_result however from the links provided above it's not too clear where this should be implemented.

实现应在初始调用方法中进行.因此，当get_content()方法调用get_template()方法时，应在此处以以下方式实现:

Implementation should take place in the initial calling method. So, as the get_content() method calls the get_template() method it should be implemented here in the following manner:

    private function get_content($pageId){
    $retreiveContent = $this->con->prepare("SELECT template_id, section_title, i1, i2 FROM content WHERE page_id=? ORDER BY sequence DESC");
    $retreiveContent->bind_param('i',$pageId);
    $retreiveContent->execute();
    $retreiveContent->bind_result($template_id, $section_title, $i1, $i2);
    $retreiveContent->store_result();
         while ($retreiveContent->fetch()) {
            //Variables will be populated for this row.
            //Update the tags in the template.
            $template = $this->get_template($template_id);
            $template = str_replace('[i1]',$i1,$template);
            $template = str_replace('[i2]',$i2,$template);
            //$theTemplate is populated with content. Probably want to echo here
            echo $template;
        }
    $retreiveContent->free_result();    
    $retreiveContent->close();
}

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