如何让桨停在窗口边界

Question

所以我已经为pong克隆编写了代码，我正在努力让paddles停止超出窗口界限。继承人我正在使用的代码

if (this->getPosition().y < 0)
    {
        this->move(0, 1.0f);
    }
    else if (this->getPosition().y + this->getGlobalBounds().height > 600);
    {
        this->move(0, -1.0f);
    }

不，当我这样做时，桨不会向底部移动，但会向顶部移动并离开屏幕。当我注释掉这个 - >移动（0，-1.0f）时，拨片将停在屏幕顶部，但会从屏幕底部移开。继承头文件：

#pragma once
#include "entity.h"

class paddle_player : public Entity
{
public: 
paddle_player(int playerNumber)
{
    this->playerNumber = playerNumber;
    switch (this->playerNumber)
    {
        case 0:
            this->Load("paddle1.png");
            break;
        default:
            this->Load("paddle2.png");

            break;
    }
}
void Update()
{
    switch (this->playerNumber)
    {
    case 0:
        this->velocity.y = sf::Keyboard::isKeyPressed(sf::Keyboard::Key::S) - sf::Keyboard::isKeyPressed(sf::Keyboard::Key::W);
        break;
    default:
        this->velocity.y = sf::Keyboard::isKeyPressed(sf::Keyboard::Key::Down) - sf::Keyboard::isKeyPressed(sf::Keyboard::Key::Up);
        break;



    }
    Entity::Update();
    if (this->getPosition().y < 0)
    {
        this->move(0, 1.0f);
    }
    else if (this->getPosition().y + this->getGlobalBounds().height > 600);
    {
        this->move(0, -1.0f);
    }
}
private:
int playerNumber; 
};

我不知道还有什么要包括但请帮忙！