Hidden Variable Arrays

Anon

Simple question -- just can't figure it out yet.

I have a form where I have a drop-down, multiple select list. The selections go into an array which I set up in the form as name=productid[] ....

I want to pass this on through several html pages (I'm programming a "wizard").

If I have the following code snipet on my first page:

and submit this, on page 2 I can determine with $HTTP_POST_VARS that productid=Array and I can access the values of the array on page 2.

Now I want to setup a hidden variable on page 2 to pass the array values to page 3. How do I do this so that the array values for productid are available on page 3?

Anon

Well the trick here is that when you output just the array all you get is the word "array" so you have to loop through all the values in the array and put each of them on the page as a separate hidden value.

Example Source:

//$productid[] is the array passed from the previous page.

for($i=0;$i<count($productid);$i++)
{
echo '<INPUT TYPE="hidden" NAME="productid[]" VALUE="'.$productid[$i].'">'
}

This will in esscence rebuild the original array on the second page and then when this page is sent on to your third page all the values will still be in an array named productid[]

There are many other ways to loop through and get these values on the page but this one is probably the easiest to understand.

Shaun Hawkes
helpme@phpgods.net
Victoria, B.C.
Canada

Anon

***First Page (form)
$serial = serialize($your_array);
//puts the array data into a string
$pass_data = addslashes($serial);
//escape any quotes
echo "<input type=hidden name=\"productid\" value=\"$pass_data\">";
//assign the value to a hidden form element

***Second Page (processing)
$productid = unserialize($productid);
//extract the string back into an array.
echo "<input type=hidden name=\"productid\" value=\"$productid\">";
//use this if you want to pass the data onto your third page

I don't think you have to stripslashes(), or addslashes() again, on the second page. If it gives you errors, then maybe you can throw either one in.

Serialize was made for passing arrays between pages.

---John Holmes...

Anon

Oh yeh I fergot about that one, I've only been using it for saving arrays to files to speed up database intensive scripts like news pages, forums, and chat boards, or anything else where the read to post ratio is large enough to warant it.

A quick note on your second page, it will fail because you have re-used the same variable name as such it will update the original variable to an array and will assuch write over the serialized string. Just a simple error, we aqll do it, but newbie programmers might not spot that right away.

***Second Page (processing)
$productidarray = unserialize($productid);
echo "<input type=hidden name=\"productid\" value=\"$productid\">";

Anon

Oops, you're right. This should give Paul some ideas though....

---JH

Anon

Thanks Shaun and John. Both methods work great . The serialize approach is more compact with larger arrays and the first method proposed by Shaun seems better suited for small arrays -- simply to eliminate the need for long lists of hidden variables.

Anon

if you want to save it to the database, and you only got 1 field for that, you should do this:
$productid_str = implode ("|",$productid);
$query = "isert ..... $product_str....";

Example Source:

//$productid[] is the array passed from the previous page.

for($i=0;$i<count($productid);$i++)
{
echo '<INPUT TYPE="hidden" NAME="productid[]" VALUE="'.$productid[$i].'">'
}

This will in esscence rebuild the original array on the second page and then when this page is sent on to your third page all the values will still be in an array named productid[]

There are many other ways to loop through and get these values on the page but this one is probably the easiest to understand.