使用PHP在对象中设置公共值

I want to set my value in object using public method. But I can't find to make it work

<?php
        class User{
            public $id;

            public function ToSynchData(){
                $this->$id = "1";
            }
        }
        $new = new User;
        $new->ToSynchData();
        $new->$id;
    ?>

public $id;

public function ToSynchData(){
    $this->id = 1;
}

$new = new User;
$new->ToSynchData();
echo $new->id; // 1

EDIT: Why static all of a sudden?

class User{
    public $id;
    public function ToSynchData(){
        $this->id = "1";
    }
}

$new = new User();
$new->ToSynchData();
print_r($new->id);

you are trying to access static property with -> whereas it is clearly written here

Static properties cannot be accessed through the object using the arrow operator ->.

therefore to access it you have to change it from static public to public