Thinkphp5 introduces think\ View to report error

problem description

using use thinkView to report an error, prompting think: undefined namespace think

the platform version of the problem and what methods you have tried

related codes

/ / Please paste the code text below (do not replace the code with pictures)
namespace appdemocontroller;

use thinkView;

class Index
{

public function index()
{

    $view=new View();
    return $view->fetch("index");

}

}

what result do you expect? What is the error message actually seen?

Php
Jul.06,2021

use thinkView;
 use think\View

Picture description


you, the library file does not exist. How is it possible to use? can't you find that use think\ View is red?

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3d0da-2bade.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3d0da-2bade.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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