使用php会话将值从一个页面发送到另一个页面[重复]

Question

This question already has an answer here:

• how to pass value from one php page to another using session 2 answers

Im using wordpress
I wanted to send the data that is collected by form in the first page to the next page
I didn't find anything that can send array data to another page other than GET command, GET commands uses URL, The reason I'm not using this GET is the sending information includes price values that are calculated using entered information

I found this $_session seems ok to my case (If any others are available, please tell me), Used wp session manager plugin to use $_SESSION.
im using it like this,

if(!isset($_SESSION)){
    session_start();}

if(isset($_GET['B2'])) {
$_SESSION["info"] = "user-form";
$_SESSION["weight"] = $weight;
$_SESSION["price"] = $weight;
buy_now(); }

The B2 is a buy now button

function buy_now(){
 if(isset($_GET['B2'])) {
 header("Location:".get_site_url()."/buy-now/");
 } 

 if(!isset($_SESSION)){
    session_start();}
        echo $_SESSION["info"]."<br>";
        echo $_SESSION["weight"]."<br>";
        echo $_SESSION["price"]."<br>";
 }

The weight and price are Undefined index, the info will display.
What is the problem here? and How can I send variables to another page?, I'm unable to find any solution for now. Please help with this...
Thank you

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Answer 1

whenever you are need to check the session is start of not you should not check ist with $_SESSION you need to check the session_id() is generated or not (check the post for check the session start Check if PHP session has already started)

if (session_status() == PHP_SESSION_NONE) {
    session_start();
}
if(isset($_GET['B2'])) {
   $_SESSION["info"] = "user-form";
   $_SESSION["weight"] = $weight;
   $_SESSION["price"] = $weight;
   buy_now(); 
}