php - 当我向数据库发出新请求时的问题视图

Question

我有一个表格。在那里您应该能够注册新用户。但它也应该检查用户名是否已经存在。如果我们假设一个人想要注册自己但他的用户名已经存在。所以我们提出了一个“用户名已经存在”的文本。当他再次尝试注册时不会丢失错误消息但会留下

class RegisterController {

public function DoControllNewUser() {
    $Validation = new Validation();
    $Stringer = "";
    //..skapar
    $RegisterView = New RegisterView();
    $UserHandler = new UserHandler();

    if ($RegisterView -> TriedTocreateNewUser()) {
        if ($Validation -> ValidateUserName($RegisterView -> GetUserName()) == TRUE && ($Validation -> ValidatePassword($RegisterView -> GetPassword(), $RegisterView -> GetSecondPassword()) == TRUE)) {

            $UserHandler -> DoCreateNewUser($RegisterView -> GetUserName(), $RegisterView -> GetPassword());
            if($UserHandler -> DoCreateNewUser($RegisterView -> GetUserName(), $RegisterView -> GetPassword()) == false){
                $Stringer .= "Användarnamnet finns redan hos oss!";
            }
            else{
        #   $RegisterView -> ChangeAction(true);
            $Stringer .= $RegisterView -> NewMemberMessage();
            }

        }
        if ($Validation -> ValidateUserName($RegisterView -> GetUserName()) == TRUE && ($Validation -> ValidatePassword($RegisterView -> GetPassword(), $RegisterView -> GetSecondPassword()) == false))
            $Stringer .= $RegisterView->WrongSecondPasswordMessage();
            return $Stringer;
    }
    $Stringer .= $Validation -> ShowErrorMessages();
    return $Stringer;
}

}