C# - 防止图片框离开边界

Question

我有一个名为玩家的图片框和4个图片框，它们在游戏开始时充当边界。我有这个代码，如果按下一个键，就会执行：

private void HorrorForm_KeyDown(object sender, KeyEventArgs e)

        {

            int x = player.Location.X;

            int y = player.Location.Y;

            if (e.KeyCode == Keys.D)

                x += 7;

            if (e.KeyCode == Keys.A)

                x -= 7;

            if (e.KeyCode == Keys.S)

                y += 7;

            if (e.KeyCode == Keys.W)

                y -= 7;

            if (player.Bounds.IntersectsWith(openspot1.Bounds) || player.Bounds.IntersectsWith(openspot2.Bounds) || player.Bounds.IntersectsWith(openspot3.Bounds) || player.Bounds.IntersectsWith(openspot4.Bounds))

            {

                player.Location = new Point(player.Location.X - 1, player.Location.Y - 1);

            }

            player.Location = new Point(x, y);

        }

如何移动玩家，但阻止他离开边界？

Answer 1

有一种观点与你的代码不正确，至少我认为是这样。你总是把球员移动到他的新位置。你一定要检查他是否触及了界限。如果他触及边界，你把他向上移动一个像素，向左移动一个像素，只是为了将他移动到7个像素到所选的direktion中。因此，在你检查他是否触及边界的地方，你必须中断，不要执行设置新位置的其余代码。一个简单的将完成这项工作。ifreturn;如果按下一个键，你将进行边界检查，如果玩家没有触及边界，你将移动玩家。这是错误的顺序。你必须检查玩家在移动后是否会触及边界，只有当他不会触摸边界移动他时。否则，你会把他移入边界，再也不把他赶出去。所以这是你的代码和一些更正：private void HorrorForm_KeyDown(object sender, KeyEventArgs e){    int x = player.Location.X;    int y = player.Location.Y;    if (e.KeyCode == Keys.D)        x += 7;    if (e.KeyCode == Keys.A)        x -= 7;    if (e.KeyCode == Keys.S)        y += 7;    if (e.KeyCode == Keys.W)        y -= 7;    var tempPlayerPosition= player.Bounds; // get the players position and remember it temporary    tempPlayerPosition.X = x; // change the players temporary pisition to the new one that it will have after the move    tempPlayerPosition.Y = y;    //check if the play would touch the boundyries if we use the new temporary pisition    if (tempPlayerPosition.IntersectsWith(openspot1.Bounds) ||         tempPlayerPosition.IntersectsWith(openspot2.Bounds) ||         tempPlayerPosition.IntersectsWith(openspot3.Bounds) ||         tempPlayerPosition.IntersectsWith(openspot4.Bounds))    {        return; //if he would touch the boundary, then do nothing    }    player.Location = new Point(x, y); //if he would not touch the boundary, move him to his new location}但也许你也想防止在按下不是 W、S、A 或 D 的键时执行代码（即使他没有改变任何值）。使用而不是这样使它更具可读性。switchif而不是每次都写数字7，使用局部变量，所以如果将来会改变，你只需要改变一个值。所以我的建议是这样的：private void HorrorForm_KeyDown(object sender, KeyEventArgs e){        var oneStep = 7; // define the amount of pixel the player will be moved    var tempPlayerPosition = player.Bounds;// get the players position and remember it temporary    switch (e.KeyCode) // check which key was presses    {        case Keys.D:            tempPlayerPosition.X += oneStep; // move right            break;        case Keys.A:            tempPlayerPosition.X -= oneStep; // move left            break;        case Keys.S:            tempPlayerPosition.Y += oneStep; // move down            break;        case Keys.W:            tempPlayerPosition.Y -= oneStep; // move up            break;         default: // you may wan't to do nothing if there any other key presses...            return;    }    //check if the play would touch the boundyries if we use the new temporary pisition    if (tempPlayerPosition.IntersectsWith(openspot1.Bounds) ||         tempPlayerPosition.IntersectsWith(openspot2.Bounds) ||         tempPlayerPosition.IntersectsWith(openspot3.Bounds) ||         tempPlayerPosition.IntersectsWith(openspot4.Bounds))    {        return; //if he would touch the boundary, then do nothing    }    player.Location = new Point(tempPlayerPosition.X, tempPlayerPosition.Y);   //if he would not touch the boundary, move him to his new location}这对你有帮助吗？