win7自动壁纸切换小工具AutoDesk三：全局热键

全局热键，博客园有很多现成的文章，下面的实现感觉封装的比较好，用起来也比较方便（感谢博客园的网友）

using System;  
using System.Runtime.InteropServices;  
  
namespace SystemHotKey  
{  
    public delegate void HotkeyEventHandler(int HotKeyID);  
  
    public class Hotkey : System.Windows.Forms.IMessageFilter  
    {  
        System.Collections.Hashtable keyIDs = new System.Collections.Hashtable();  
        IntPtr hWnd;  
  
        public event HotkeyEventHandler OnHotkey;  
  
        public enum KeyFlags  
        {  
            MOD_ALT = 0x1,  
            MOD_CONTROL = 0x2,  
            MOD_SHIFT = 0x4,  
            MOD_WIN = 0x8  
        }  
        [DllImport("user32.dll")]  
        public static extern UInt32 RegisterHotKey(IntPtr hWnd, UInt32 id, UInt32 fsModifiers, UInt32 vk);  
  
        [DllImport("user32.dll")]  
        public static extern UInt32 UnregisterHotKey(IntPtr hWnd, UInt32 id);  
  
        [DllImport("kernel32.dll")]  
        public static extern UInt32 GlobalAddAtom(String lpString);  
  
        [DllImport("kernel32.dll")]  
        public static extern UInt32 GlobalDeleteAtom(UInt32 nAtom);  
  
        public Hotkey(IntPtr hWnd)  
        {  
            this.hWnd = hWnd;  
            System.Windows.Forms.Application.AddMessageFilter(this);  
        }  
  
        public int RegisterHotkey(System.Windows.Forms.Keys Key, KeyFlags keyflags)  
        {  
            UInt32 hotkeyid = GlobalAddAtom(System.Guid.NewGuid().ToString());  
            RegisterHotKey((IntPtr) hWnd, hotkeyid, (UInt32) keyflags, (UInt32) Key);  
            keyIDs.Add(hotkeyid, hotkeyid);  
            return (int) hotkeyid;  
        }  
  
        public void UnregisterHotkeys()  
        {  
            System.Windows.Forms.Application.RemoveMessageFilter(this);  
            foreach (UInt32 key in keyIDs.Values)  
            {  
                UnregisterHotKey(hWnd, key);  
                GlobalDeleteAtom(key);  
            }  
        }  
  
        public bool PreFilterMessage(ref System.Windows.Forms.Message m)  
        {  
            if (m.Msg == 0x312)  
            {  
                if (OnHotkey != null)  
                {  
                    foreach (UInt32 key in keyIDs.Values)  
                    {  
                        if ((UInt32) m.WParam == key)  
                        {  
                            OnHotkey((int) m.WParam);  
                            return true;  
                        }  
                    }  
                }  
            }  
            return false;  
        }  
    }  
}  

该类的使用方法：

在窗体的类中声明一个变量 
private int Hotkey1
在窗体的Load事件中加入如下代码 

/// <summary>
/// 窗体启动时挂载全局快捷键Ctrl+F1.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void AutoDesk_Load(object sender, EventArgs e)
{
try
{

SystemHotKey.Hotkey hotkey;
hotkey = new SystemHotKey.Hotkey(this.Handle); 

//定义快键(Ctrl + F1) 
Hotkey1 = hotkey.RegisterHotkey(System.Windows.Forms.Keys.F1, SystemHotKey.Hotkey.KeyFlags.MOD_CONTROL);
hotkey.OnHotkey += new SystemHotKey.HotkeyEventHandler(OnHotkey);

}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}

热键的响应函数如下：

/// <summary>
        /// 快捷键按下后切换到下一个随即壁纸。
        /// </summary>
        /// <param name="HotkeyID"></param>
         public void OnHotkey(int HotkeyID)  
         {
             try
             {
                 if (HotkeyID == Hotkey1)
                 {
                     switch_to_next_waller();
                 }
                 else
                 {
                     //this.Visible = false;  
                 }
             }
             catch (Exception ex)
             {
                 MessageBox.Show(ex.Message);
             }
         }