按钮

1. 按钮点击改变背景颜色

using System;
using System.Drawing;
using System.Windows.Forms;

public class ButtonColorForm : Form
{
    private Button lastClickedButton = null;
    private readonly Color highlightColor = Color.LightSkyBlue;

    public ButtonColorForm()
    {
        // 创建3个示例按钮
        var button1 = CreateButton("按钮1", 50);
        var button2 = CreateButton("按钮2", 150);
        var button3 = CreateButton("按钮3", 250);

        this.Text = "按钮颜色切换示例";
        this.ClientSize = new Size(300, 350);
        this.Controls.AddRange(new Control[] { button1, button2, button3 });
    }

    private Button CreateButton(string text, int yPos)
    {
        var btn = new Button
        {
            Text = text,
            Size = new Size(200, 80),
            Location = new Point(50, yPos),
            Font = new Font("Microsoft YaHei", 12),
            Tag = Color.Transparent // 存储原始颜色
        };
        btn.Click += Button_Click;
        return btn;
    }

    private void Button_Click(object sender, EventArgs e)
    {
        var currentButton = (Button)sender;

        // 恢复上一个按钮的颜色
        if (lastClickedButton != null && lastClickedButton != currentButton)
        {
            lastClickedButton.BackColor = (Color)lastClickedButton.Tag;
        }

        // 存储当前按钮原始颜色
        if (currentButton.Tag == null || (Color)currentButton.Tag == Color.Transparent)
        {
            currentButton.Tag = currentButton.BackColor;
        }

        // 设置新颜色
        currentButton.BackColor = highlightColor;
        lastClickedButton = currentButton;
    }

    [STAThread]
    public static void Main()
    {
        Application.EnableVisualStyles();
        Application.Run(new ButtonColorForm());
    }
}

2. 异步操作

using System;
using System.Threading.Tasks;
using System.Windows.Forms;

public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();
        btnStartTask.Click += BtnStartTask_Click;
    }

    private void BtnStartTask_Click(object sender, EventArgs e)
    {
        // 更新状态标签
        lblStatus.Text = "任务开始...";
        lblResult.Text = string.Empty;

        // 使用 Task.Run 在后台线程上执行任务
        Task.Run(() =>
        {
            // 模拟耗时操作，例如计算斐波那契数列的第N项
            int result = Fibonacci(30); // 计算斐波那契数列的第30项，这是一个耗时操作
            return result;
        })
        .ContinueWith(task =>
        {
            if (task.IsFaulted)
            {
                // 处理异常情况
                MessageBox.Show("任务执行过程中发生错误: " + task.Exception.InnerException.Message);
            }
            else if (task.IsCompleted)
            {
                // 在UI线程上更新标签，因为ContinueWith默认在后台线程执行
                Invoke((MethodInvoker)delegate
                {
                    lblStatus.Text = "任务完成";
                    lblResult.Text = "结果: " + task.Result.ToString();
                });
            }
        }, TaskScheduler.FromCurrentSynchronizationContext()); // 使用当前同步上下文，确保在UI线程上执行后续操作
    }

    private int Fibonacci(int n)
    {
        if (n <= 1) return n;
        return Fibonacci(n - 1) + Fibonacci(n - 2);
    }
}