如何在PreTranslateMessage(MSG*PMSG)中从WM_KEYDOWN中提取字符

Question

在从cview继承的preTranslateMessage(MSG*PMSG)中的MFC应用程序中，我有以下内容：

if (pMsg->message == WM_KEYDOWN) ...

const int virtualKey = pMsg->wParam;
const int hardwareScanCode = (pMsg->lParam >> 16) & 0x00ff; // bits 16-23

例如，在我的非美国键盘上，当我按下“#”字符时，我会得到以下内容：

virtualKey == 0xde --> VK_OEM_7 "Used for miscellaneous characters; it can vary by keyboard."
hardwareScanCode == 0x29 (41 decimal)

我想“捕获”或以不同方式处理的字符是ASCII“#”，0x23(35小数）。

我的问题

MapVirtualKey(virtualkey, MAPVK_VSC_TO_VK);
// previous line is useless, the key VK_OEM_7 doesn't map to anything without the scan code

ToAscii(virtualKey, hardwareScanCode, nullptr, &word, 0);
// previous line returns zero, and zero is written to `word`

Answer 1

我相信这是一个更好的解决办法。这一个是用标准的美国键盘布局和加拿大-法国键盘布局测试的。

const int wParam = pMsg->wParam;
const int lParam = pMsg->lParam;
const int keyboardScanCode = (lParam >> 16) & 0x00ff;
const int virtualKey = wParam;

BYTE keyboardState[256];
GetKeyboardState(keyboardState);

WORD ascii = 0;
const int len = ToAscii(virtualKey, keyboardScanCode, keyboardState, &ascii, 0);
if (len == 1 && ascii == '#')
{
    // ...etc...
}

尽管帮助页似乎暗示keyboardstate对于调用toascii()是可选的，但我发现它对于我试图检测的字符是必需的。