accessing connection variable in a while loop - php

Question

I am trying to acces my connection variable while I run a while loop, yet when I try to call a function, it bogus out on me and PHP gives me the so called boolean error when I try to prepare my statement within the function.
I debugged it to the point that I know my variable $CategorieId is being pushed on and I do get a array return of $con when I do a print_r in the function itself. However when I try to acces it when I prepare my statement, it just returns me a boolean, thus creating the error in the dropdown, not being able to fill it up.
The setup is as followed.
dbControl.php
$con = mysqli_connect('localhost','root','','jellysite') or die("Error " . mysqli_error($con));
function OpenConnection(){
global $con;
if (!$con){
die('Er kan geen verbinding met de server of met de database worden gemaakt!');
}
}
functionControl.php
function dropdownBlogtypeFilledin($con,$CategorieId){
echo "<select name='categorie' class='dropdown form-control'>";
$sql = "SELECT categorieId, categorieNaam
FROM categorie";
$stmt1 = mysqli_prepare($con, $sql);
mysqli_stmt_execute($stmt1);
mysqli_stmt_bind_result($stmt1,$categorieId,$categorieNaam);
while (mysqli_stmt_fetch($stmt1)){
echo "<option value='".$categorieId."'.";
if( $categorieId == $CategorieId){
echo "selected='selected'";
}
echo ">".$categorieNaam."</option>";
}
echo "</select>";
}
Blogedit.php
<?php
require_once '../db/dbControl.php';
require_once '../db/functionControl.php';
session_start();
OpenConnection();
$id = $_SESSION['user'];
?>
// some html up to the while loop
<?php
$a = $_GET['a'];
$sql = "SELECT blog.blogId,
blog.blogTitel,
blog.blogCategorieId,
blog.blogSynopsis,
blog.blogInhoud
FROM blog
WHERE blog.blogId = ? ";
$stmt1 = mysqli_prepare($con, $sql);
mysqli_stmt_bind_param($stmt1,'i',$a);
mysqli_stmt_execute($stmt1);
mysqli_stmt_bind_result($stmt1, $blogId, $Titel, $CategorieId, $Synopsis, $Inhoud );
while (mysqli_stmt_fetch($stmt1)){
$Synopsis = str_replace('\r\n','', $Synopsis);
$Inhoud = str_replace('\r\n','', $Inhoud);
?>
// again some HTML
<?php dropdownBlogtypeFilledIn($con,$CategorieId); ?>
// guess what, more html!
<?php
}
?>
Does anyone know how I can solve it? I tried it with the global variable (the OpenConnection() function) but it didn't seem to work.
Edit
I confirm it has indeed to do with the $con variable. I tested it by defining the $con variable again in the function, and it printed perfectly what I wanted. Its a bad solutions. I just prefer to have it defined once.
The weird thing is that it happens only when i put it in a while loop. I have a create form which is exactly the same, except there is no while loop, since I create it all from scratch and there is no PHP involved on that part. I have there a dropdown function as well, which also requires the $con variable, but there it works. I really think it has to do with the while loop.

Answer 1

I solved it for now by creating a new instance of the connection variable before i initiated the prepared statement of the page retrieving the information.
<?php
$connection = $con;
$a = $_GET['a'];
$sql = "SELECT blog.blogId,
blog.blogTitel,
blog.blogCategorieId,
blog.blogSynopsis,
blog.blogInhoud
FROM blog
WHERE blog.blogId = ? ";
mysqli_stmt_init($con);
$stmt1 = mysqli_prepare($con, $sql);
mysqli_stmt_bind_param($stmt1,'i',$a);
mysqli_stmt_execute($stmt1);
mysqli_stmt_bind_result($stmt1, $blogId, $Titel, $CategorieId, $Synopsis, $Inhoud );
mysqli_stmt_store_result($stmt1);
while (mysqli_stmt_fetch($stmt1)){
$Synopsis = str_replace('\r\n','', $Synopsis);
$Inhoud = str_replace('\r\n','', $Inhoud);
<?php dropdownBlogtypeFilledIn($connection ,$CategorieId); ?>
?>
With the variable $connection I could initiate the function that required the connection details within the while call. I am not sure if there is a cleaner option here, but indeed I read somewhere that I couldn't use the same connection variable if I am already using it in a prepared statement. Appearantly I cannot ride this one the same connection variable, and that seemed to be the problem. I will look into this and hope I dont have to write a while bunch of connection variables whenever I have multiple dropdowns for example that pull information from the database.