最近遇到一個問題，在一個WinForm窗口中，按ALT+Z能夠?qū)崿F(xiàn)最小化到托盤及從托盤回復(fù)正常窗口。
剛開始，試著在窗口的KeyPress事件中添加，但是當(dāng)窗口最小化到托盤后，焦點已經(jīng)不在窗口上了，因此將不能捕捉鍵盤按鍵按下的事件，因此不能從托盤彈出。經(jīng)測試，這種方法是錯誤的。
既然KeyPress事件不能解決問題，那么為什么不能添加熱鍵呢？
添加熱鍵的方法是
BOOL RegisterHotKey(
HWND hWnd,
int id,
UINT fsModifiers,
UINT vk
);
其中參數(shù)hWnd是注冊熱鍵的窗口句柄，id是熱鍵的標(biāo)識符，fsModifiers是在創(chuàng)建WM_HOTKEY消息時必須跟用戶定義的按鍵一同按下的特殊組合鍵，他的值為：
| Value |
Description |
| MOD_ALT |
Either ALT key must be held down. |
| MOD_CONTROL |
Either CTRL key must be held down. |
| MOD_KEYUP |
Both key up events and key down events generate a WM_HOTKEY message. |
| MOD_SHIFT |
Either SHIFT key must be held down. |
| MOD_WIN |
Either WINDOWS key was held down. These keys are labeled with the Microsoft Windows logo. |
我們可以使用這個函數(shù)注冊我們的熱鍵。
在C#中使用這個函數(shù)，我們必須從user32.dll中將此函數(shù)導(dǎo)入，而且必須重寫WndProc函數(shù)來捕捉熱鍵消息。
以下為示例代碼：
[DllImport("user32.dll")]
public static extern bool RegisterHotKey(IntPtr hWnd, int id, uint control, Keys vk);
[DllImport("user32.dll")]
public static extern bool UnregisterHotKey(IntPtr hWnd, int id);
private void Form1_Load(object sender, EventArgs e)
{
RegisterHotKey(this.Handle, 888, 1, Keys.Z);
this.Hide();
this.ShowInTaskbar = true;
this.comboBox1.SelectedIndex = 0;
}
protected override void WndProc(ref Message m)
{
switch (m.Msg)
{
case 0x0312:
if (m.WParam.ToString().CompareTo("888") == 0)
{
if (bIsShowed)
{
this.Hide();
this.ShowInTaskbar = true;
this.WindowState = FormWindowState.Minimized;
this.notifyIcon1.Visible = true;
this.bIsShowed = false;
}
else
{
this.Visible = true;
this.ShowInTaskbar = false;
this.WindowState = FormWindowState.Normal;
this.Activate();
this.notifyIcon1.Visible = false;
bIsShowed = true;
}
UnregisterHotKey(this.Handle, 888);
RegisterHotKey(this.Handle, 888, 1, Keys.Z);
}
break;
default:
break;
}
base.WndProc(ref m);
}