PDO: Erhalten Fehler: Rufen Sie auf eine Elementfunktion vorbereiten() auf einem Nicht-Objekt

Question

beim Ausführen dbconfig.php (unten beschrieben) Erste Fehler wie:

PHP Fatal error: Call to a member function prepare() on a non-object in Class.crud.php on line 13 
PHP Stack trace: 
PHP 1. {main}() dbconfig.php:0 
PHP 2. crud->create() dbconfig.php:16 

Datei: dbconfig.php

<?php 
    $db_host = "localhost"; 
    $db_user = "root"; 
    $db_pass = "95111991"; 
    $db_name = "php_pdo_db"; 

    try{ 
     $db_con = new PDO("mysql:host={$db_host}; dbname = {$db_name}",$db_user,$db_pass); 
     $db_con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
    } 
    catch (PDOException $e){ 
     echo $e->getMessage(); 
    } 
    include_once 'Class.crud.php'; 

    $crud = new crud($db_con); 
?> 

Datei: Class.crud.php

<?php 
class crud 
{ 
    private $db; 

    function _construct($db_con) 
    { 
     $this->db = $db_con; 
    } 
    public function create($fname,$lname,$email) 
    { 
     try{ 
      $stmt = $this->db->prepare("INSERT INTO tbl_user(Firstname,Lastname,Email) VALUES (:fname,:lname, :email)"); 
      $stmt ->bindparam(":fname", $fname); 
      $stmt ->bindparam(":lname", $lname); 
      $stmt ->bindparam(":email", $email); 
      $stmt->execute(); 
      return true; 
     }catch (PDOException $e){ 
      echo $e->getMessage(); 
      return false; 
     } 
    } 
    public function getID($id){ 
     $stmt = $this->db->prepare("SELECT * FROM tbl_user WHERE ID = :id"); 
     $stmt->execute(array(":id"=>$id)); 
     $editRow=$stmt->fetch(PDO::FETCH_ASSOC); 
     return $editRow; 
    } 
    public function update($id,$fname,$lname,$email) 
    { 
     try{ 
      $stmt=$this->db->prepare("UPDATE tbl_user SET Firstname = :fname, 
            Lastname = :lname, Email = :email WHERE ID = :id"); 
      $stmt->bindparam(":fname",$fname); 
      $stmt->bindparam(":lname",$lname); 
      $stmt->bindparam(":email",$email); 
      $stmt->bindparam(":id",$id); 
      $stmt->execute(); 

      return true; 
     }catch (PDOException $e){ 
      echo $e -> getMessage(); 
      return false; 
     } 
    } 
    public function delete($id) 
    { 
     $stmt = $this->db->prepare("DELETE FROM tbl_user WHERE ID = :id"); 
     $stmt->bindparam(":id",$id); 
     $stmt->execute(); 
     return true; 
    } 

    /* paging */ 
    public function dataview($query) 
    { 
     //global $db_con 
     $stmt = $this->db->prepare($query); 
     $stmt->execute(); 

     if($stmt->rowCount()>0){ 
      while($row=$stmt->fetch(PDO::FETCH_ASSOC)) 
      { 
       ?> 
        <tr> 
        <td><?php print($row['ID']); ?></td> 
        <td><?php print($row['Firstname']); ?></td> 
        <td><?php print($row['Lastname']); ?></td> 
        <td><?php print($row['Email']); ?></td> 
        <td align = "center"> 
         <a href = "edit_data.php?edit_id=<?php print($row['ID']); ?>"><i class = "glyphicon glyphicon-edit"></i></a> 
        </td> 
        <td align = "center"> 
         <a href = "delete_data.php?delete_id=<?php print($row['ID']); ?>"><i class = "glyphicon glyphicon-remove-circle"></i></a> 
        </td> 
        </tr> 
        <?php 
      } 
     } 
     else{ 
      ?> 
        <tr> 
        <td>Nothing here...</td> 
        </tr> 
        <?php 
     } 
    } 
    public function paging($query,$records_per_page) 
    { 
     $starting_position = 0; 
     if(isset($_GET["page_no"])) 
     { 
      $starting_position = ($_GET["page_no"]-1)*$records_per_page; 
     } 
     $query2 = $query." limit $starting_position, $records_per_page"; 
     return $query2; 
    } 
    public function paginglink($query,$records_per_page) 
    { 
     $self = $_SERVER['PHP_SELF']; 

     $stmt = $this->db->prepare($query); 
     $stmt->execute(); 

     $total_no_of_records = $stmt->rowCount(); 

     if($total_no_of_records > 0){ 
      ?><ul class = "pagination"><?php 
      $total_no_of_page = ceil($total_no_of_records/$records_per_page); 
      $current_page = 1; 
      if(isset($_GET["page_no"])) 
      { 
       $current_page = $_GET["page_no"]; 
      } 
      if($current_page != 1) 
      { 
       $previous = $current_page-1; 
       echo "<li><a href = '".$self."?page_no=1'>First</a></li>"; 
       echo "<li><a href = '".$self."?page_no=".$previous."'>Previous</a></li>"; 
      } 
      for($i = 1; $i <= $total_no_of_page; $i++) 
      { 
       if($i == $current_page) 
       { 
        echo "<li><a href = '".$self."?page_no=".$li."' style = 'color:red;'>".$i."</a></li>"; 
       } 
       else{ 
        echo "<li><a href = '".$self."?page_no=".$i."'>".$i."</a></li>"; 
       } 
      } 
      if($current_page != $total_no_of_page) 
      { 
       $next = $current_page+1; 
       echo "<li><a href = '".$self."?page_no=".$next."'>Next</a></li>"; 
       echo "<li><a href = '".$self."?page_no=".$total_no_of_page."'>Last</a></li>"; 
      } 
      ?></ul><?php 
     } 
    } 
    /* paging */ 
} 
?> 

Wie kann ich diesen Fehler beheben?

Answer 1

in Ihrem class crud Sie geschrieben haben:

function _construct($db_con) 

Verwenden __construct Statt _construct

function __construct($db_con)