VC中的RegisterHotKey函式與HotKey控制元件(CHotKeyCtrl)
1、其實，關於RegisterHotKey函式本人寫過一個簡單的示例，主要是利用這個函式實現全域性熱鍵。
2、本文記錄的重點是通過Hot Key控制元件設定的熱鍵，如何正確的用RegisterHotKey函式註冊。
3、思路很清晰，將使用者在控制元件的輸入通過函式GetHotKey獲得，獲取到的值包括兩個，一個是熱鍵的組合型別，譬如Ctrl + X、Shift + X、ALT + X或者Ctrl + Shift + X，而另一個就是X。
4、但是，我們發現直接將GetHotKey獲取到的值代入RegisterHotKey函式執行，有時會出問題。當然，這裡所謂的問題不是編譯的問題，而是當你註冊了一個熱鍵，卻發現一直不進熱鍵的訊息函式。
5、具體的情況是：
（1）形如Ctrl + X的熱鍵一切正常；
（2）形如Shift + X和Alt + X的熱鍵不響應；
... ...
6、如果細心的朋友會發現，當你在控制元件中設定熱鍵為Shift + X並直接呼叫函式RegisterHotKey時，其實註冊的結果是Alt + X。也就是說，Shift和Alt這兩個值搞反了。
7、那麼，是不是一個Bug呢？我們不放仔細看一下兩者的定義：
（1）RegisterHotkey函式第三個引數的說明：
fsModifiers [in] Specifies keys that must be pressed in combination with the key specified by thenVirtKey| 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. |
Call this function to retrieve the virtual key code and modifier flags of a hot key from a hot key control.
DWORD GetHotKey( ) const; void GetHotKey( WORD &, WORD & ) const;
Parameters
- wVirtualKeyCode
- Virtual key code of the hot key. For a list of standard virtual key codes, see Winuser.h.
- wModifiers
- Modifier flags indicating the keys that, when used in combination with wVirtualKeyCode, define a hot key combination.
Return Value
In the first usage above, a DWORD containing the virtual key code and modifier flags. The low-order word is the virtual key code, and the high-order word is the modifier flags. The HIWORD and LOWORD of this 32-bit value can be used as the parameters in the SetHotKey member function.
Remarks
The modifier flags can be a combination of the following values:
- HOTKEYF_ALT ALT key
- HOTKEYF_CONTROL CTRL key
- HOTKEYF_EXT Extended key
- HOTKEYF_SHIFT SHIFT key
8、注意我標紅的地方，下面我們看一下定義：
（1）Microsoft SDKs\Windows\v7.0A\Include\WinUser.h
#define MOD_ALT 0x0001
#define MOD_CONTROL 0x0002
#define MOD_SHIFT 0x0004
|
（2）Microsoft SDKs\Windows\v7.0A\Include\CommCtrl.h
#define HOTKEYF_SHIFT 0x01
#define HOTKEYF_CONTROL 0x02
#define HOTKEYF_ALT 0x04
|
9、這下問題清楚了，提供兩個轉換函式：
UINT ModToHotkey(UINT fsModifiers)
{
if ( (fsModifiers & MOD_SHIFT) && !(fsModifiers & MOD_ALT) ) // shift轉alt
{
fsModifiers &= ~MOD_SHIFT;
fsModifiers |= HOTKEYF_SHIFT;
}
else if ( !(fsModifiers & MOD_SHIFT) && (fsModifiers & MOD_ALT) ) // alt轉shift
{
fsModifiers &= ~MOD_ALT;
fsModifiers |= HOTKEYF_ALT;
}
return fsModifiers;
}
UINT HotkeyToMod(UINT fsModifiers)
{
if ( (fsModifiers & HOTKEYF_SHIFT) && !(fsModifiers & HOTKEYF_ALT) ) // shift轉alt
{
fsModifiers &= ~HOTKEYF_SHIFT;
fsModifiers |= MOD_SHIFT;
}
else if ( !(fsModifiers & HOTKEYF_SHIFT) && (fsModifiers & HOTKEYF_ALT) ) // alt轉shift
{
fsModifiers &= ~HOTKEYF_ALT;
fsModifiers |= MOD_ALT;
}
return fsModifiers;
}
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