Application.AddMessageFilter可以帮你监视所有系统发送到Form的讯息
我们利用它来过滤讯息
便可以做出我们需要的热键
这是Application.AddMessageFilter的呼叫方式
必须传递一个IMessageFilter的对象当做参数
public static void AddMessageFilter(
IMessageFilter value
)
我们这边做一个继承IMessageFilter界面的HotKey类别
class HotKey : IMessageFilter
{
...
}
然后在HotKey类别里使用两个属性记录热键的组合方式
并在HotKey建立时给予初始值
Keys _hotKey = Keys.None;
Keys _comboKey = Keys.None;
public HotKey(Keys hotKey, Keys comboKey)
{
_hotKey = hotKey; //热键
_comboKey = comboKey; //组合键, 必须设定Keys.Control, Keys.Alt, Keys.Shift, Keys.None等值才有作用
Application.AddMessageFilter(this); //使用HotKey类别来监视讯息
}
IMessageFilter接口还必须实作一个PreFilterMessage方法
用来监视/过滤我们要的讯息
当我们按下正确的热键时
它会触发自定义的事件OnHotKey
public delegate void HotkeyEventHandler(object sender, EventArgs e);
public event HotkeyEventHandler OnHotkey; //自定义事件
const int WM_KEYDOWN = 0x100; //按下键盘的讯息
const int WM_ALTKEYDOWN = 0x104; //按下Alt键的讯息
public bool PreFilterMessage(ref Message m)
{
if (OnHotkey != null && (m.Msg == WM_KEYDOWN || m.Msg == WM_ALTKEYDOWN)) //当键盘按下时
{
if (((Keys)(int)m.WParam & Keys.KeyCode) == _hotKey && Control.ModifierKeys == _comboKey) //如果热键+组合键相符
{
OnHotkey(this, null); //触发自定义事件
return true; //并拦截这个讯息, Form将不再接收到这个讯息
}
}
return false;
}
到这边我们就完成了一个简单版的HotKey了
我们来测试看看
在Form1_Load里产生四组热键
private void Form1_Load(object sender, EventArgs e)
{
HotKey hotkey = new HotKey(Keys.A, Keys.Alt); //注册Alt+A为热键
hotkey.OnHotkey += new HotKey.HotkeyEventHandler(hotkey_OnHotkey);
HotKey hotkey2 = new HotKey(Keys.B, Keys.Control); //注册Ctrl+B为热键
hotkey2.OnHotkey += new HotKey.HotkeyEventHandler(hotkey2_OnHotkey);
HotKey hotkey3 = new HotKey(Keys.C, Keys.Shift); //注册Shift+C为热键
hotkey3.OnHotkey += new HotKey.HotkeyEventHandler(hotkey3_OnHotkey);
HotKey hotkey4 = new HotKey(Keys.F2, Keys.None); //注册F2为热键, 如果不要组合键请传Keys.None当参数
hotkey4.OnHotkey += new HotKey.HotkeyEventHandler(hotkey4_OnHotkey);
}
void hotkey_OnHotkey(object sender, EventArgs e)
{
MessageBox.Show("热键Alt+A被按下了");
}
void hotkey2_OnHotkey(object sender, EventArgs e)
{
MessageBox.Show("热键Ctrl+B被按下了");
}
private void hotkey3_OnHotkey(object sender, EventArgs e)
{
MessageBox.Show("热键Shift+C被按下了");
}
private void hotkey4_OnHotkey(object sender, EventArgs e)
{
MessageBox.Show("热键F2被按下了");
}
http://www.dotblogs.com.tw/sam319/archive/2010/01/06/12876.aspx