使用带有html格式的sql表中的sql表中的数据

Question

I'm trying to create a form in html which has a combobox with a list that's automatic created from my SQL table. I've managed to make an integrated combobox in my class where I use all my database statements. But how do I use the code on another location where my form is written? I'm still learning php and this is kinda new for me so I hope my question is clear to understand.

Code:

    class Lesdb
    {
        private static $lesdbInstantie = null;

        private $dbh;

        private function __construct($server, $username, $password, $database)
        {
            try
            {
                $this->dbh = new PDO("mysql:host=$server; dbname=$database", $username, $password);
                //Bij error: exception opwerpen
                $this->dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            }
            catch (PDOException $e)
            {
                die($e->getMessage());
            }
        }

        public static function getLesdbInstantie($server, $username, $password, $database)
        {
            if(is_null(self::$lesdbInstantie))
            {
                self::$lesdbInstantie = new Lesdb($server, $username, $password, $database);
            }
            return self::$lesdbInstantie;
        }
    public function testComboBox()
    {
        echo "<h1> ComboBox functienamen </h1>";

            $sql = "SELECT DISTINCT ftienaam FROM werknemers";
            $stmt = $this->dbh->prepare($sql);
            $stmt->execute();

        $dropdown = "<select name='ftienaam'>";
        foreach ($stmt as $row)
        {
            $dropdown .= "\r\n<option value='{$row['ftienaam']}'>{$row['ftienaam']}</option>";
        }
        $dropdown .= "\r\n</select>";

        echo $dropdown;

    }
}

?>

The function TestCombobox does work but it should be implemented into my form which isn't located in the class Lesdb. example :

function ShowForm()
{
    ?>
    <form action="Index.php?actie=zoekInLijst" method=post>
        <label for=ComboBox>ComboBox</label>
            <select name = "the_name">
                <option value="name">SQL STATEMENTS
            </select>
    </form>
<?php
}

So I simply want to call the function testComboBox from the class Lesdb in my form.

Answer 1

Assuming your class is in one file, let's call it Lesdb.php and your form is in another file, eg Form.php, then you have to include your class in the form file (right at the top, before the other code),

include_once "<PATH_TO_YOUR_FILE>\Lesdb.php";

create an instance of your class (where you want to use that instance),

Lesdb db = new Lesdb();

and use the function in your ShowForm function.

db->testComboBox();

Answer 2

You have to make an new instance of the class. Then on that instance you have to load the function.

Don't forget to include the class in top of the file.

$theLesDB = new Lesdb();

$theLesDB->testComboBox();