c# - Move PictureBox using Arrow Keys - 处理 PictureBox 中的键盘事件

Question

我有一个 PictureBox，我在其中使用下面的代码来移动我的对象。我需要在表单中添加一些按钮，但是当我启动程序时，箭头键在按钮之间导航，而不是我的输入按键。我试过很多Form.Load() 上的 PictureBox.Focus() 和 PictureBox.Select() 之类的方法，并在此完全禁用箭头键导航回答here , 但我的对象将不再移动。

private void UpdateScreen(object sender, EventArgs e) {

    if (Input.KeyPressed(Keys.Right) && Settings.direction != Direction.Left) {
        Settings.direction = Direction.Right;
    }
    else if (Input.KeyPressed(Keys.Left) && Settings.direction != Direction.Right) {
        Settings.direction = Direction.Left;
    }  
    else if (Input.KeyPressed(Keys.Up) && Settings.direction != Direction.Down) {
        Settings.direction = Direction.Up;
    }
    else if (Input.KeyPressed(Keys.Down) && Settings.direction != Direction.Up) {
        Settings.direction = Direction.Down;
    }
}

如何在不影响 UpdateScreen() 中的代码的情况下禁用所有按钮的箭头键导航？

Answer 1

PictureBox 控件不是Selectable，因此它无法处理键盘事件。要解决这个问题，首先应该使控件可选:

using System;
using System.Windows.Forms;
class SelectablePictureBox : PictureBox
{
    public SelectablePictureBox()
    {
        SetStyle(ControlStyles.Selectable, true);
        SetStyle(ControlStyles.UserMouse, true);
        TabStop = true;
    }

    protected override void OnEnter(EventArgs e)
    {
        base.OnEnter(e);
        this.Invalidate();
    }
    protected override void OnLeave(EventArgs e)
    {
        base.OnLeave(e);
        this.Invalidate();
    }
    protected override void OnPaint(PaintEventArgs pe)
    {
        base.OnPaint(pe);
        if (this.Focused)
            ControlPaint.DrawFocusRectangle(pe.Graphics, ClientRectangle);
    }
}

然后你可以处理它的PreviewKeyDown事件:

private void selectablePictureBox1_PreviewKeyDown(object sender,
    PreviewKeyDownEventArgs e)
{
    if (e.KeyCode == Keys.Left)
    {
        e.IsInputKey = true;
        myPictureBox1.Left -= 10;
    }
    else if (e.KeyCode == Keys.Right)
    {
        e.IsInputKey = true;
        myPictureBox1.Left += 10;
    }
}