从POST获取动态变量

Question

I want to randomize a number of users selected by an administrator.

So first, I have a page that reads all the name from the "Users" table. Then I display the names with a checkbox next to it so the admin can deselect names that aren't going to participate.

<input name="User<? echo $rows['UserID']; ?>" type="checkbox" value="1" checked/>

So, it will set values like User1 = 1; User2 = 0; User3 = 1, and so on...

Next, I want to write to the database the users that were selected in the form so I can read that table again to randomize the participants. How do I read the dynamic variable from the previous form? I'm trying to read the variable from the POST and store it in the variable Player (ie: User1 value is stored in Player1 variable)... this but doesn't seem to work:

    $x = 1;
while ($x <= $total_records) {
    ${"Player" . $x} = $_POST[ ${"User" . $x} ];
    $x++;
    echo "Player" . $x . " = " . ${"Player" . $x} . "<BR>";
}

The result is "Player1 = ", "Player2 = ". Always empty.

Any idea, or an easier way to do it? ;) Thanks!

Answer 1

I would recommend a separate approach. Instead of creating a different name for each checkbox, how about making them an array and their values are the users' ids?

For instance:

<input type="checkbox" name="User[]" value="<? echo $rows['UserID']; ?>" />

Then, you'll only have to iterate over the submitted array:

if (isset($_POST['User']) && is_array($_POST['User'])) {
    foreach ($_POST['User'] as $userId) {
        // do something with the user id!
    }
}

If you want to keep the list as, well, a "list" to be reused, you could implode() the array that's posted and explode() when you need to use it again:

$combinedIds = implode(',', $_POST['User']);
// now you have 1,3,17

$splitIds = explode(',', $combinedIds);
// now you have array(1, 3, 17)

You can store the list in the db, a session variable, etc. If you store in a session variable, you could also directly store the array (whichever's easier =P).