C# 键盘事件处理程序矩形

Question

我是 C# 新手，尝试创建一个键盘事件。它应该在按下 W、A、S 或 D 键时显示。首先我的计划是显示一些 pictureBox 并且如果按下右键就改变图片。

但后来我在互联网上搜索，在 Java http://docs.oracle.com/javase/8/javafx/sample-apps/KeyboardExample.zip 中找到了类似的东西它看起来像这样：

据我所知，代码正在绘制一个带有一些字母的矩形。我查看了 msdn 并找到了一个绘制矩形的示例： https://msdn.microsoft.com/de-de/library/sx8yykw8(v=vs.110).aspx

不幸的是我卡在了绘图中。通常我使用工具箱向表单添加内容。然后我双击它并在大括号内写下我的代码。但是工具箱里没有"Rectangle"，不知道怎么添加

到目前为止，这是我的代码：

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        //Stay always on top
        this.TopMost = true;
        //Does not work. Removes border but you can't move the window after this
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        //Can I delete this?            
    }

    private void Form1_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (e.KeyChar >= 65 && e.KeyChar <= 122)
        {
            switch (e.KeyChar)
            {
                //If pressed w or W
                case (char)119:
                case (char)87:
                    Console.WriteLine(e.KeyChar);
                    break;
                //If pressed a or A
                case (char)97:
                case (char)65:
                    Console.WriteLine(e.KeyChar);
                    break;
                //If pressed s or S
                case (char)83:
                case (char)115:
                    Console.WriteLine(e.KeyChar);
                    break;
                //If pressed d or D
                case (char)100:
                case (char)68:
                    Console.WriteLine(e.KeyChar);
                    break;
                //Other keys
                default:
                    lblMessage.Text = "Key not supported";
                    //does not work
                    //timer1_Tick();
                    break;
            }
        }
    }

    private void timer1_Tick(object sender, EventArgs e)
    {
        lblMessage.Hide();
    }
}

这是我的表单现在的样子：

我目前遇到的其他问题：

如何从 Form1_KeyPress 调用计时器以在几秒后隐藏 lblMessage？
删除边框而不失去移动 window 的能力（例如 this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;）

编辑：我将代码更改为最新的工作状态。

Answer 1

欢迎来到 Windows 桌面编程的世界！

这里有两个选择；你可以：

使用设计视图将组件添加到 WASD 表单（因为你有 W、A、S、D 框，看起来你已经添加了它们）和你的 Form1_KeyPress() 处理程序，只需更新框的属性。这可以像下面这样简单，只要确保将其更改为正确的组件名称即可：

//If pressed w or W
case (char)119:
case (char)87:
        Console.WriteLine(e.KeyChar);
        button1.BackColor = Color.Red;//Highlight W
        button2.BackColor = Color.Empty;//Ignore A
        button3.BackColor = Color.Empty;//Ignore S
        button3.BackColor = Color.Empty;//Ignore D
        break;

覆盖窗体的 OnDraw() 处理程序并直接在屏幕上绘制框。这更难，但会给你更多的力量。

关闭标签很容易。在您的 Form1_Load() 处理程序中确保设置 timer1 的超时属性：

private void Form1_Load(object sender, EventArgs e)
{
    timer1.Interval = 5000;//In ms = thousandths-of-a-second
}

在 Form1_KeyPress() 处理程序中打开计时器：

private void Form1_KeyPress(object sender, KeyPressEventArgs e)
{
    ...
    lblMessage.Enabled = true;
    timer1.Start();
}

做你的工作并关闭 timer1_Tick() 处理程序中的计时器：

private void timer1_Tick(object sender, EventArgs e)
{
    lblMessage.Enabled = false;
    timer1.Stop();
}

Answer 2

这是我快速整理的内容：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WASD_Keyboard
{
    public partial class Form1 : Form
    {
        private PictureBox pictureBox1 = new PictureBox();
        private bool wPressed = false;
        private bool aPressed = false;
        private bool sPressed = false;
        private bool dPressed = false;
        private Timer timer = new Timer();

        public Form1()
        {
            InitializeComponent();
            //Stay always on top
            this.TopMost = true;
            //Does not work. Removes border but you can't move the window after this
            this.FormBorderStyle = FormBorderStyle.None;

            timer.Interval = 3000;
            //this is an event binding
            timer.Tick += timer1_Tick;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // Dock the PictureBox to the form and set its background to white.
            pictureBox1.Dock = DockStyle.Fill;
            pictureBox1.BackColor = Color.White;
            pictureBox1.Paint += DrawRectangleRectangle;
            // Add the PictureBox control to the Form.
            this.Controls.Add(pictureBox1);
        }

        private void Form1_KeyPress(object sender, KeyPressEventArgs e)
        {
            // reversed logic to stop nesting
            if (e.KeyChar < 65 || e.KeyChar > 122) return;

            wPressed = false;
            aPressed = false;
            sPressed = false;
            dPressed = false;
            //this should really be multiple if statement so it can do more than one key
            //If pressed w or W
            if (e.KeyChar == (char) 119 || e.KeyChar == (char) 87) {
                wPressed = true;
                Console.WriteLine(e.KeyChar);
            }

            //If pressed a or A
            if (e.KeyChar == (char) 97 || e.KeyChar == (char) 65) {
                aPressed = true;
                Console.WriteLine(e.KeyChar);
            }

            //If pressed s or S
            if (e.KeyChar == (char) 83 || e.KeyChar == (char) 115) {
                sPressed = true;
                Console.WriteLine(e.KeyChar);
            }

            //If pressed d or D
            if (e.KeyChar == (char) 100 || e.KeyChar == (char) 68) {
                dPressed = true;
                Console.WriteLine(e.KeyChar);
            }

            if (!wPressed && !aPressed && !sPressed && !dPressed) {
                //Something goes wrong
                lblMessage.Text = "Key not supported";
                return;
            }

            pictureBox1.Refresh();
            // in older .net if you didn't do both you ran into multiple issues
            timer.Enabled = true;
            timer.Start();
        }

        public void DrawRectangleRectangle(object sender, PaintEventArgs e)
        {
            DrawRectangle(e, new Point(40, 10), new Size(20, 20), 'W', wPressed ? Color.Red : Color.White);
            DrawRectangle(e, new Point(10, 40), new Size(20, 20), 'A', aPressed ? Color.Red : Color.White);
            DrawRectangle(e, new Point(40, 40), new Size(20, 20), 'S', sPressed ? Color.Red : Color.White);
            DrawRectangle(e, new Point(70, 40), new Size(20, 20), 'D', dPressed ? Color.Red : Color.White);
        }

        public void DrawRectangle(PaintEventArgs e, Point p, Size s, char letter, Color c)
        {
            // Create pen.
            var blackPen = new Pen(Color.Black, 3);
            var brush = new SolidBrush(c);
            // Create rectangle.
            var rect = new Rectangle(p, s);

            // Draw rectangle to screen.
            e.Graphics.DrawRectangle(blackPen, rect);
            e.Graphics.FillRectangle(brush, rect);
            e.Graphics.DrawString(letter.ToString(), new Font(FontFamily.GenericSerif, 12), Brushes.Blue, rect);
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            wPressed = false;
            aPressed = false;
            sPressed = false;
            dPressed = false;

            timer.Enabled = false;
            timer.Stop();
            pictureBox1.Refresh();
        }
    }
}

注意：这是高度异步但不使用任何锁定...

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