如何使用Laravel将变量从一个控制器传递到另一个控制器

Question

To begin with the user selects a value from the dropdown list which stores the selected value in a variable called $SetNumber which is located in ControllerOne. Once the user selects from the dropdown as you cans see the form action is /Update which is used to retrieve and redirect the data to ControllerTwo

<form method="POST" action="/Update">
    @csrf 
    <select name="Match" id="Match" onchange="this.form.submit()">
        <option value="1">1</option>
        <option value="2">2</option>
        <option value="3">3</option>
    </select>
</form> 

ControllerOne contains an empty variable, which defines the variable $SetNumber. ControllerOne:

class ControllerOne extends Controller
{
    public function index()
    {
        $SetNumber = "";
    }


    public function update(Request $request)
    {
         $SetNumber = $request->Match;

         return redirect()->action('ControllerTwo@index', ['SetNumber' => $SetNumber]);
    }   
}



class ControllerTwo extends Controller
{
    public function index()
    {
        echo $SetNumber;

        return view('pages.viewpage')->with('SetNumber', $SetNumber);
    }
}

The problem is that when I try to echo $SetNumber within my controller and return it to my view , prompts me with this error:

Undefined variable: SetNumber.

how could I do this better?

i am new to laravel and web dev.

Answer 1

The parameters sent with the redirect function are added to the query string of the generated url. So if you want to access them in the other controllers function, you have to get the value from the request object.

class ControllerTwo extends Controller
{
    public function index()
    {
        $SetNumber = request()->get('SetNumber');
        return view('pages.spotifyApi')->with('SetNumber', $SetNumber);
    }
}