C++ WM_KEYDOWN - 捕获按键引起的事件
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WM_KEYDOWN - capturing keypress causing event
提问by CaptainProg
I am trying to do a very simple task - have an event occur when a key is pressed - but am having a lot of difficulty implementing it.
我正在尝试做一个非常简单的任务 - 按下某个键时会发生一个事件 - 但我在实现它时遇到了很多困难。
I am using the Win32 API. I have been asked what framework I am using but I don't know that. I am using Visual C++ and the program is a Windows program.
我正在使用 Win32 API。有人问我正在使用什么框架，但我不知道。我正在使用 Visual C++，该程序是一个 Windows 程序。
All I want to do is have an event occur if a specific key is pressed. For this example I am using the 's' key, and the event is an integer either being set to 1 or 0; whichever it wasn't set to at the time of the key press (I would use bool but I don't know how it works just yet).
我想要做的就是在按下特定键时发生事件。在这个例子中，我使用了 's' 键，事件是一个被设置为 1 或 0 的整数；无论在按键时未设置为哪个（我会使用 bool 但我还不知道它是如何工作的）。
I have been told to use GetKeyState(), and then told that this is actually no good. I have also been told to use WM_KEYDOWN but can't work out how this works... Surely what I am doing must be absolute basic programming (keyboard input > output) but I can't get a clear explanation as to how it works?!
有人告诉我使用 GetKeyState()，然后告诉我这实际上不好。我也被告知要使用 WM_KEYDOWN 但无法弄清楚它是如何工作的......当然我所做的必须是绝对的基本编程（键盘输入>输出），但我无法清楚地解释它是如何工作的？！
I have tried using the following, with no luck:
我尝试使用以下方法，但没有运气：
int Flag;
if (GetKeyState(115) == 1 && Flag == 0) Flag = 1;
if (GetKeyState(115) == 1 && Flag == 1) Flag = 0;
I have also tried using this:
我也试过使用这个：
if (GetKeyState(115) & 0x8000 && Flag == 0) Flag = 1;
if (GetKeyState(115) & 0x8000 && Flag == 1) Flag = 0;
Neither work. Does anyone know how I could implement WM_KEYDOWN?
都不工作。有谁知道我如何实现 WM_KEYDOWN？
I am using a Windows Message Loop
我正在使用 Windows 消息循环
回答by MerickOWA
There are several ways to solve this problem. None of which will give you "nano-second" accuracy but here they are.
有几种方法可以解决这个问题。这些都不会给你“纳秒”的精度，但它们就是这样。
If you want the keypress to be recieved by an active window or dialog you handle a WM_KEYDOWN even in the WINPROC of the dialog/window like so.
如果您希望按键被活动窗口或对话框接收，即使在对话框/窗口的 WINPROC 中也可以像这样处理 WM_KEYDOWN。
void InSomePlace()
{
WNDCLASS wndClass
ZeroMemory( &wndClass, sizeof(wndClass) );
// Initialize wndClass members here
wndClass.lpszClassName = _T("MyWindow");
wndClass.lpfnWndProc = &MyWndProcHandler; //
RegisterClass( &wndClass );
HWND hWnd = CreateWindow( _T("MyWindow", /* lots of other parameters */ );
MSG msg;
BOOL bRet;
while ( (bRet = GetMessage( &msg, hWnd, 0, 0 )) != 0 )
{
if (bRet == -1)
{
// handle the error and possibly exit
}
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
}
LRESULT CALLBACK MyWndProcHandler( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam )
{
switch ( uMsg )
{
// Lots of case statements, in particular you want a WM_KEYDOWN case
case WM_KEYDOWN:
if ( wParam == 'S' )
{
// Do something here
return 0L;
}
break;
}
return DefWindowProc( hwnd, uMsg, wParam, lParam );
}
For a DialogBox its very similar, you would still have a DLGPROC which is passed as the last parameter to DialogBox/CreateDialog
对于非常相似的 DialogBox，您仍然会有一个 DLGPROC，它作为最后一个参数传递给 DialogBox/CreateDialog
void InSomePlace( HINSTANCE hInstance, HWND hParentWindow )
{
DialogBox( hInstance, _T("MyDialogTemplate"), hParentWindow, &MyDialogProc );
}
INT_PTR CALLBACK MyDialogProc( HWND hwndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam )
{
case ( uMsg )
{
// Lots of case statements, in particular you want a WM_KEYDOWN case
case WM_KEYDOWN:
if ( wParam == 'S' )
{
// Do something here
SetWindowLong(hwndDlg, DWL_MSGRESULT, 0L);
return TRUE;
}
break;
}
return FALSE;
}
