[英]Can't handle WM_KEYDOWN message
我正在尝试使用以下 wndproc 和 winmain 处理 WM_KEYDOWN 消息,但是当我按下一个键(即 ascii 值为 24、25、26、27 的箭头键)时,它没有被处理。
WndProc
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam){
/*TO CHECK uMsg message*/
char buff[256];
_itoa_s(uMsg, buff, 10);
SetWindowText(hEdit, buff);
/**********************/
switch (uMsg)
case WM_CREATE:
hEdit = CreateWindowEx(WS_EX_CLIENTEDGE, "Edit", "", WS_CHILD | WS_VISIBLE |ES_AUTOVSCROLL | ES_MULTILINE | ES_WANTRETURN | WS_VSCROLL, 735, 5, 150, 100, hWnd, NULL, hInst, NULL);
HButton1 = CreateWindowEx(NULL, "BUTTON", "START", WS_CHILD | WS_VISIBLE | SS_CENTER, 2, 2, 80, 20, hWnd, (HMENU)IDC_BUTTON1, hInst, NULL);
HButton2 = CreateWindowEx(NULL, "BUTTON", "B", WS_CHILD | WS_VISIBLE | SS_CENTER, 82, 2, 80, 20, hWnd, (HMENU)IDC_BUTTON2, hInst, NULL);
HButton3 = CreateWindowEx(NULL, "BUTTON", "STOP", WS_CHILD | WS_VISIBLE | SS_CENTER, 162, 2, 80, 20, hWnd, (HMENU)IDC_BUTTON3, hInst, NULL);
Hmainbmp = CreateWindowEx(NULL, "STATIC", "", WS_CHILD | WS_VISIBLE | SS_BITMAP | WS_THICKFRAME, 1, 23, 600, 500, hWnd, NULL, hInst, NULL);
break;
case WM_KEYDOWN:
PRESSED_KEY = wParam;
break;
case WM_COMMAND:
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return(DefWindowProc(hWnd, uMsg, wParam, lParam));
return(0L);
}
WinMain
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow){
MSG msg;
WNDCLASSEX wc;
HMENU MainMenu, FileMenu;
MainMenu = CreateMenu();
FileMenu = CreatePopupMenu();
AppendMenu(FileMenu, MF_STRING, IDC_OPEN, "Open");
AppendMenu(MainMenu, MF_POPUP, (UINT_PTR)FileMenu, "FILE");
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = (WNDPROC)WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON1));
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW);
wc.lpszMenuName = lpszAppName;
wc.lpszClassName = lpszAppName;
wc.cbSize = sizeof(WNDCLASSEX);
wc.hIconSm = (HICON)LoadImage(hInstance, lpszAppName, IMAGE_ICON, 16, 16, LR_DEFAULTCOLOR);
if (!RegisterClassEx(&wc)) return(FALSE);
hInst = hInstance;
hWnd = CreateWindowEx(0, lpszAppName, lpszTitle, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 900, 600, NULL, MainMenu, hInstance, NULL);
if (!hWnd) return(FALSE);
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return (int)msg.wParam;
}
为什么下面的情况不起作用? 我该如何处理 WM_KEYDOWN?
case WM_KEYDOWN:
PRESSED_KEY = wParam;
break;
更新
当我再次最小化和最大化 window 时, WM_KEYDOWN
已处理,但如果我单击任何按钮,它就不起作用。
根据WM_KEYDOWN
文件:
发布到 window 按下非系统键时键盘焦点。 非系统键是在未按下 ALT 键时按下的键。
但是你的window里面还有其他的按钮和编辑框,所以当你按下其他按钮或者点击编辑框的时候,焦点会在那个window上,导致WndProc
function无法处理WM_KEYDOWN
消息。
可以使用SetFocus
function设置键盘焦点window。然后可以通过主window获取WM_KEYDOWN
消息,通过Edit控件显示数值。
像下面的代码:
case WM_KEYDOWN:
PRESSED_KEY = wParam;
_itoa_s(wParam, buff, 10);
SetWindowTextA(hEdit, buff);
break;
当然,如果你不想专注于特定的window来获取键盘信息,我建议你使用SetWindowsHookEx
function来获取全局键盘信息,而不是专注于特定的window。
编辑:
如果你想处理所有的WM_KEYDOWN
消息,你可以使用SetWindowsHookEx
function。
您只需要修改代码的几个部分:
1.添加一个function来处理键盘:
LRESULT __stdcall KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
char buff[256] = "";
PKBDLLHOOKSTRUCT key = (PKBDLLHOOKSTRUCT)lParam;
//a key was pressed
if (wParam == WM_KEYDOWN && nCode == HC_ACTION)
{
_itoa_s(key->vkCode, buff, 10);
SetWindowTextA(hEdit, buff);
}
return CallNextHookEx(NULL, nCode, wParam, lParam);
}
2.在main function中设置对键盘的hook进程:
HHOOK _k_hook;
int WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPSTR szCmdLine, _In_ int nCmdShow)
{
MSG msg;
WNDCLASSEX wc;
HMENU MainMenu, FileMenu;
_k_hook = SetWindowsHookEx(WH_KEYBOARD_LL, KeyboardProc, NULL, 0);
...
}
3.最后,程序结束后别忘了删除hook进程:
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
HWND HButton1, HButton2, HButton3, Hmainbmp;
switch (uMsg)
{
...
case WM_DESTROY:
if (_k_hook)
UnhookWindowsHookEx(_k_hook);
PostQuitMessage(0);
break;
...
}
}
这样就不需要在WndProc
中处理WM_KEYDOWN
的消息了。 按键消息在KeyboardProc
function中处理,在Edit控件中显示按键的值。
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