Incapable of catching error in if clause (updated with answer) - php

Question

In this code below, $alb->error has an error message in it. I can verify this with echo, no problem.
The issue arises when I want to catch that error in an if clause. First, the code:
if($action == "add")
{
//PUT CODE TO SAVE A NEW ALBUM HERE
//SHOULD RETURN ALBUM ID
$alb = new album();
//fill object album with properties to be saved
$alb->date = checkNull($_POST['alb_date']);
$alb->name = checkNull($_POST['alb_name']);
$alb->desc = checkNull($_POST['alb_desc']);
$alb->cat_id = $_POST['categories'];
//call save method of album
$alb->create_album();
//catch error
if($alb->error <> "")
{
header("Location: add_album.php?error='$alb->error'");
}
//set album id to pass it along to add_pictures
$alb_id = $alb->id;
}
elseif($action == "edit")
{
//PUT CODE TO SAVE EDITED ALBUM HERE
//SHOULD RETURN ALBUM ID
}
header("Location: add_pictures.html?alb_id='$alb_id'");
After $alb->create_album(), $alb's error property is filled by omitting a required field in the input form. This is what I want. But then, I need to catch that error, and redirect the user to the previous page, where the error will be displayed.
Here's what I've tried so far:
//catch error
if(isset($alb->error))
{
header("Location: add_album.php?error='$alb->error'");
}
Didn't work.
//catch error
if(!is_null($alb->error))
{
header("Location: add_album.php?error='$alb->error'");
}
No cigar.
//catch error
if($alb->error <> "")
{
header("Location: add_album.php?error='$alb->error'");
}
still, zero joy.
The if clause never gets processed. What am I missing?
Thank you for your time.

Answer 1

So the problem was that I had a header redirect after my outer if clause for the type of action: if action=add or edit. When I wrapped it in an else clause, it worked:
}
elseif($action == "edit")
{
//PUT CODE TO SAVE EDITED ALBUM HERE
//SHOULD RETURN ALBUM ID
}
else
{
header("Location: add_pictures.html?alb_id='$alb_id'");
}
Thanks for your help!!