用 C# 實現截圖功能（三）：熱鍵註冊與系統匣圖示實作（中）

4. 使用熱鍵及系統匣圖示

程式啟動時最小化至系統匣，按下熱鍵啟動截圖。於 MainForm 中實現：

• 加入 NotifyIcon 控制項，設定 Icon 與 Visible = true。
• 專案屬性 Settings 中新增熱鍵相關設定（如 HotKey、isAltHotKey）。

using System;
using System.Drawing;
using System.Windows.Forms;
using System.ComponentModel;
using ScreenCutter.Properties;

namespace ScreenCutter
{
    public enum KeyModifiers
    {
        None = 0, Alt = 1, Control = 2, Shift = 4, Windows = 8
    }

    public partial class MainForm : Form
    {
        private ContextMenu contextMenu1;
        private MenuItem menuItem1, menuItem2;
        private ScreenBody body;

        public MainForm()
        {
            InitializeComponent();
            this.components = new Container();
            contextMenu1 = new ContextMenu();
            menuItem2 = new MenuItem { Index = 0, Text = "S&et HotKey" };
            menuItem1 = new MenuItem { Index = 1, Text = "E&xit" };
            menuItem1.Click += menuItem1_Click;
            menuItem2.Click += menuItem2_Click;
            contextMenu1.MenuItems.AddRange(new[] { menuItem2, menuItem1 });
            notifyIcon1.ContextMenu = contextMenu1;
            notifyIcon1.Text = "Screen Cutter";
            notifyIcon1.Visible = true;
            body = null;
        }

        private void MainForm_SizeChanged(object sender, EventArgs e)
        {
            if (this.WindowState == FormWindowState.Minimized)
            {
                this.Hide();
                notifyIcon1.Visible = true;
            }
        }

        private void CutScreen()
        {
            Image img = new Bitmap(Screen.AllScreens[0].Bounds.Width, Screen.AllScreens[0].Bounds.Height);
            Graphics g = Graphics.FromImage(img);
            g.CopyFromScreen(Point.Empty, Point.Empty, Screen.AllScreens[0].Bounds.Size);
            body = new ScreenBody { BackgroundImage = img };
            body.Show();
        }

        private void ProcessHotkey(Message m)
        {
            IntPtr id = m.WParam;
            if (id.ToString() == "100") CutScreen();
        }

        private void MainForm_Load(object sender, EventArgs e)
        {
            uint ctrHotKey = (uint)KeyModifiers.Control;
            if (Settings.Default.isAltHotKey)
                ctrHotKey = (uint)(KeyModifiers.Alt | KeyModifiers.Control);
            HotKey.RegisterHotKey(Handle, 100, ctrHotKey, Settings.Default.HotKey);
        }

        private void MainForm_FormClosing(object sender, FormClosingEventArgs e)
        {
            HotKey.UnregisterHotKey(Handle, 100);
        }

        protected override void WndProc(ref Message m)
        {
            const int WM_HOTKEY = 0x0312;
            if (m.Msg == WM_HOTKEY) ProcessHotkey(m);
            base.WndProc(ref m);
        }

        private void menuItem1_Click(object sender, EventArgs e)
        {
            HotKey.UnregisterHotKey(Handle, 100);
            notifyIcon1.Visible = false;
            this.Close();
        }

        private void menuItem2_Click(object sender, EventArgs e)
        {
            new SetHotKey().ShowDialog();
        }
    }
}