【delphi】关于窗口接收键盘按键的问题,求指导~

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窗口的KeyPreview设置为true,窗口上有若干按钮。程序启动时,窗口能响应键盘按键消息,但是如果点击过窗口上的按钮以后(按钮为选中状态,等于按钮的default为true时的效果),这是窗口就不能响应键盘按键了,请问如何处理啊!
感觉原因就是,点击按钮以后,焦点停留在按钮上的原因,设置添加form.setFocus,无效。
.......
按照sirouszlh的提议安装了HotKeySpy控件,我只在子窗口中使用了该控件,但是我关闭子窗口后回到出窗口,设置的热键还在起作用,请问怎么处理呢?

下载一个HotKeySpy控件就可以了 很简单了
虽然有bug 但基本可以用
我自己就修改成适合自己的追问

安装了HotKeySpy控件,我只在子窗口中使用了该控件,但是我关闭子窗口后回到出窗口,设置的热键还在起作用,请问怎么处理呢?

追答

退出时,设置HotKeySpy1.HotKeys[0].Enabled:=false;

参考技术A 搜索一下delphi 键盘 钩子追问

试了,按网上的例子编译没有通过呀

《Windows程序设计》读书笔六 键盘

6.1 键盘基础


6.1.1 忽略键盘

6.1.2 谁获得了焦点?

窗口过程通过WM_SETFOCUS和WM_KILLFOCUS消息来确定自己的窗口是否具有输入焦点


6.1.3 队列和同步

6.1.4 击键和字符

应用程序从windows接受的关于键盘事件的消息可分为击键和字符两种。

有些按键参数击键消息和字符消息

有些按键只产生击键消息


6.2 击键消息


6.2.1 系统键击和非系统键击

应用程序通常忽略WM_SYSKEYUP 和WM_SYSKEYDOWN消息,将他交给DefWindowProc来处理

如果你捕捉了也要再交给DefWindowProc处理

不与Alt组合会产生WM_KEYDOWN和WM_KEYUP消息。


6.2.2 虚拟键代码

虚拟键代码存储在WM_KEYDOWN, WM_KEYUP, WM_SYSKEYDOWN,  WM_SYSKEYUP 的wParam中。

以VK开头,定义在winuser.h文件中





还有许多按键参考P179页


6.2.3 lparam信息


重复计数


OEM扫描码


扩展键标记


内容代码


键的先前状态


转换状态


6.2.4 转义状态

shift, Ctrl Alt 或者CapsLock NumLock Scroll Lock

iState = GetKeyState(VK_SHIFT);   //如果shift被按下 iState为负,高位置1


iState = GetKeyState(VK_CAPITAL); //如果CapsLock按键打开,低位置1.


也可以获得VK_LBUTTON, VK_RBUTTON, VK_MBUTTON得到鼠标按钮的状态。

GetKeyState 无法获得功能键的状态

可以使用

GetAsyncKeyState


6.2.5 使用击键消息

windows通常不产生字符的击键使用WM_KEYDOWN消息,尽管可以通过击键消息和转义状态信息把击键转换为字符。你会在非英语键盘上遇到问题


对于光标移动,功能键,Insert Delete  , WM_KEYDOWN 消息是最有用的。 但是Insert, Delete 经常被用作菜单快捷键。因为Windows会把菜单快捷键转换为菜单命令消息,所以应用程序不必自己处理这些击键。

总之大部分时间,你仅需要处理光标移动的WM_KEYDOWN 消息,有时候处理Insert Delete 的WM_KEYDOWN消息。当使用这些键时,可以通过GetKeyState函数来检查Shift和Ctrl犍的状态。


6.2.6 为SYSMETS加上键盘处理功能

system.h 代码

参见第四章

system.cpp 加入键盘控制的代码主要是把相应的键盘操作映射为相应的ScrollBar消息,简化代码。

#include <windows.h>
#include "sysmets.h"


LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); //window procedure.

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
	PSTR szCmdLine, int iCmdShow)
{
	static		TCHAR szAppName[] = TEXT("SysMets4");
	HWND		hwnd;
	MSG			msg;
	WNDCLASS	wndClass;		//The window Class

	wndClass.style = CS_HREDRAW | CS_VREDRAW;
	wndClass.lpfnWndProc = WndProc;// assign the window procedure to windows class.
	wndClass.cbClsExtra = 0;
	wndClass.cbWndExtra = 0;
	wndClass.hInstance = hInstance;
	wndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
	wndClass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
	wndClass.lpszMenuName = NULL;
	wndClass.lpszClassName = szAppName;

	//Register the Window Class to the Windows System. 
	if (!RegisterClass(&wndClass))
	{
		MessageBox(NULL, TEXT("This program require Windows NT!"),
			szAppName, MB_ICONERROR);
		return 0;
	}

	//This function will generate an WM_CREATE message.
	hwnd = CreateWindow(szAppName,		//Window class name
		TEXT("Get System Metrics No. 4"),		//Window caption
		WS_OVERLAPPEDWINDOW | WS_VSCROLL | WS_HSCROLL,			//Window Style
		CW_USEDEFAULT,					//initial x position
		CW_USEDEFAULT,					//initial y position
		CW_USEDEFAULT,					//initial x size
		CW_USEDEFAULT,					//initial y size
		NULL,							//parent window handle
		NULL,							//window menu handle
		hInstance,						//program instance handle
		NULL);							//creation parameters

	ShowWindow(hwnd, iCmdShow);
	UpdateWindow(hwnd);	//This function will generate a WM_PAINT message.

						/* The message loop for this program.
						if received the WM_QUIT message, the function will return 0.*/
	while (GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return msg.wParam;

}

//define the Window Procedure WndProc
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	static int	cxChar, cxCaps, cyChar, cxClient, cyClient, iMaxWidth;
	HDC			hdc;
	int			i, x, y, iVertPos, iHorzPos, iPaintBeg, iPaintEnd;
	PAINTSTRUCT	ps;
	SCROLLINFO	si;
	TCHAR		szBuffer[10];
	TEXTMETRIC	tm;

	switch (message) //get the message
	{
	case WM_CREATE:
		hdc = GetDC(hwnd);

		GetTextMetrics(hdc, &tm);
		cxChar = tm.tmAveCharWidth;
		cxCaps = (tm.tmPitchAndFamily & 1 ? 3 : 2)* cxChar / 2;
		cyChar = tm.tmHeight + tm.tmExternalLeading;
		ReleaseDC(hwnd, hdc);

		iMaxWidth = 40 * cxChar + 22 * cxCaps;
		return 0;
	case WM_SIZE:
		cxClient = LOWORD(lParam);
		cyClient = HIWORD(lParam);

		//Set vertical scroll bar range and page size

		si.cbSize = sizeof(si);
		si.fMask = SIF_RANGE | SIF_PAGE;
		si.nMin = 0;
		si.nMax = NUMLINES - 1;
		si.nPage = cyClient / cyChar;
		SetScrollInfo(hwnd, SB_VERT, &si, TRUE);

		//Set the horizontal scroll bar range and page size
		si.cbSize = sizeof(si);
		si.fMask = SIF_RANGE | SIF_PAGE;
		si.nMin = 0;
		si.nMax = 2 + iMaxWidth / cxChar;
		si.nPage = cxClient / cxChar;
		SetScrollInfo(hwnd, SB_HORZ, &si, TRUE);
		return 0;

	case WM_VSCROLL:
		//Get all the vertical scroll bar information

		si.cbSize = sizeof(si);
		si.fMask = SIF_ALL;
		GetScrollInfo(hwnd, SB_VERT, &si);
		//Save the position for comparison later on

		iVertPos = si.nPos;

		switch (LOWORD(wParam))
		{
		case SB_TOP:
			si.nPos = si.nMin;
			break;
		case SB_BOTTOM:
			si.nPos = si.nMax;
			break;
		case SB_LINEUP:
			si.nPos -= 1;
			break;
		case SB_LINEDOWN:
			si.nPos += 1;
			break;
		case SB_PAGEUP:
			si.nPos -= si.nPage;
			break;
		case SB_PAGEDOWN:
			si.nPos += si.nPage;
			break;
		case SB_THUMBPOSITION:
			si.nPos = si.nTrackPos;
			break;
		default:
			break;
		}

		//Set the position and then retrieve it. Due to adjustments
		//By Windows it may not be the same as the value set.

		si.fMask = SIF_POS;
		SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
		GetScrollInfo(hwnd, SB_VERT, &si);
		// if the position has changed, scroll the window and update it
		if (si.nPos != iVertPos)
		{
			ScrollWindow(hwnd, 0, cyChar*(iVertPos - si.nPos),
				NULL, NULL);
			UpdateWindow(hwnd); //instead of the invalidateRect() it will update the rect immediately.
		}
		return 0;

	case WM_HSCROLL:
		// Get all the vertical scroll bar information

		si.cbSize = sizeof(si);
		si.fMask = SIF_ALL;
		//Save the position for comparison later on

		GetScrollInfo(hwnd, SB_HORZ, &si);
		iHorzPos = si.nPos;
		switch (LOWORD(wParam))
		{
		case SB_LINELEFT:
			si.nPos -= 1;
			break;
		case SB_LINERIGHT:
			si.nPos += 1;
			break;
		case SB_PAGELEFT:
			si.nPos -= si.nPage;
			break;
		case SB_PAGERIGHT:
			si.nPos += si.nPage;
			break;
		case SB_THUMBPOSITION:
			si.nPos = si.nTrackPos;
			break;
		default:
			break;
		}

		//Set the Position and then retrieve it. Due to adjustments
		//by Windows it may not be the same as the value set.
		si.fMask = SIF_POS;
		SetScrollInfo(hwnd, SB_HORZ, &si, TRUE);
		GetScrollInfo(hwnd, SB_HORZ, &si);

		//If the position has been changed, scroll the window
		if (si.nPos != iHorzPos)
		{
			ScrollWindow(hwnd, cxChar* (iHorzPos - si.nPos), 0,
				NULL, NULL);
		}
		return 0;
	case WM_KEYDOWN:
		switch(wParam)
		{
		case VK_HOME:
			SendMessage(hwnd, WM_VSCROLL, SB_TOP, 0);
			break;
		case VK_END:
			SendMessage(hwnd, WM_VSCROLL, SB_BOTTOM, 0);
			break;
		case VK_PRIOR:
			SendMessage(hwnd, WM_VSCROLL, SB_PAGEUP, 0);
			break;
		case VK_NEXT:
			SendMessage(hwnd, WM_VSCROLL, SB_PAGEDOWN, 0);
			break;
		case VK_UP:
			SendMessage(hwnd, WM_VSCROLL, SB_LINEUP, 0);
			break;
		case VK_DOWN:
			SendMessage(hwnd, WM_VSCROLL, SB_LINEDOWN, 0);
			break;
		case VK_LEFT:
			SendMessage(hwnd, WM_HSCROLL, SB_PAGEUP, 0);
			break;
		case VK_RIGHT:
			SendMessage(hwnd, WM_HSCROLL, SB_PAGEDOWN, 0);
			break;
		}
		return 0;
	case WM_PAINT:
		hdc = BeginPaint(hwnd, &ps);
		//Get the vertical scroll bar position

		si.cbSize = sizeof(si);;
		si.fMask = SIF_POS;
		GetScrollInfo(hwnd, SB_VERT, &si);
		iVertPos = si.nPos;

		//Get horizontal scroll bar position
		GetScrollInfo(hwnd, SB_HORZ, &si);
		iHorzPos = si.nPos;

		//Find painting limits

		iPaintBeg = max(0, iVertPos + ps.rcPaint.top / cyChar);
		iPaintEnd = min(NUMLINES - 1,
			iVertPos + ps.rcPaint.bottom / cyChar);

		for (i = iPaintBeg; i <= iPaintEnd; ++i)
		{
			x = cxChar * (1 - iHorzPos);
			y = cyChar * (i - iVertPos);
			TextOut(hdc, x, y,
				sysmetrics[i].szLabel,
				lstrlen(sysmetrics[i].szLabel));

			TextOut(hdc, x + 22 * cxCaps, y,
				sysmetrics[i].szDesc,
				lstrlen(sysmetrics[i].szDesc));

			SetTextAlign(hdc, TA_RIGHT | TA_TOP);

			TextOut(hdc, x + 22 * cxCaps + 40 * cxChar, y, szBuffer,
				wsprintf(szBuffer, TEXT("%5d"),
					GetSystemMetrics(sysmetrics[i].iIndex)));
			SetTextAlign(hdc, TA_LEFT | TA_TOP);
		}
		EndPaint(hwnd, &ps);
		return 0;
	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	}
	return  DefWindowProc(hwnd, message, wParam, lParam);
}
执行结果如下



6.3 字符消息

在消息循环中 TranslateMessage函数,负责把击键消息转换为字符消息。 WM_KEYDOWN   WM_SYSKEYDOWN.

6.3.1 四类字符消息