如何按下键盘任意键后执行一个操作？

var
  Form1: TForm1;
  FirstOperation:boolean=true;
implementation{$R *.dfm}procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
if FirstOperation then
   showmessage('执行操作1')
   else
   showmessage('执行操作2');
FirstOperation:=not FirstOperation;
end;

FirstOperation:boolean=true;
这是什么意思？

FirstOperation 只是一个标志位，按过1后，切换标志来达到循环操作，如果FirstOperation 是integer类型或string，你还能做操作1->操作2——>操作3->操作1的循环，甚至更多。

这儿有个键盘钩子的示例代码，你看看吧
http://hi.baidu.com/83925com/blog/item/3c60865cffb76046fbf2c0bb.html

给你简化一下,改成你需要的unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
TForm1 = class(TForm)
    Memo1: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
private
{ Private declarations }
    procedure HotKeyDown(var Msg: Tmessage); message WM_HOTKEY;
public
{ Public declarations }
end;const
KeyMask = $80000000;
var
Form1: TForm1;
FirstOperation:boolean=true;
LogHook: HHook = 0;
LastFocusWnd: HWnd = 0;
PrvChar: Char;
HotKeyId: Integer;
implementation{$R *.dfm}function LogProc(iCode: Integer; wparam, lparam: LongInt): lresult; stdcall;
var
ch: Char;
vKey: Integer;
PEvt: ^EVENTMSG;
begin
if iCode < 0 then
begin
    Result := CallNextHookEx(LogHook, iCode, wParam, lParam);
    exit;
end;if (iCode = HC_ACTION) then
begin
    pEvt := Pointer(DWord(lParam)); //消息事件    if pEvt.message = WM_KEYDOWN then
    begin
      if FirstOperation then
         form1.Memo1.Lines.Add('执行操作1')
      else
         form1.Memo1.Lines.Add('执行操作2');
      FirstOperation:=not FirstOperation;
    end; fsdsfsdasfd
end;Result := CallNextHookEx(LogHook, iCode, wParam, lParam);
end;procedure TForm1.FormCreate(Sender: TObject);
begin
HotKeyId := GlobalAddAtom('MyHotKey') - $C000;
RegisterHotKey(Handle, hotkeyid, MOD_ALT, VK_F8);
//
if LogHook = 0 then
    LogHook := SetWindowsHookEx(WH_JOURNALRECORD, LogProc, HInstance, 0);
end;procedure TForm1.FormDestroy(Sender: TObject);
begin
if LogHook <> 0 then
begin
    UnhookWindowsHookEx(LogHook);
    LogHook := 0;
end;
end;
procedure TForm1.HotKeyDown(var Msg: Tmessage);
begin
if (Msg.LparamLo = MOD_ALT) AND (Msg.LParamHi = VK_F8) then
begin
    showmessage('ALT' + 'F8');
    form1.Visible := true;
end;
end;end.

不用把，加个全局boolean变量
按下按键先读取boolean变量的值如果是真就执行第一个函数功能
如果是假就执行第二个函数功能，
然后将boolean 变量取反，
很简单，用什么钩子啊

如钩ｆ9键，只要判断它，F9键＝ VK_F9 (120)
就行了．

要这么复杂做什么啊，做一个标志，在KEYPRESS里，执行了事件1就打上一个标记，执行了事件2就更新另一个标记，执行事件时只要根据当前的标记判断就知道该执行哪个事件了啊

ｈｏｏｋ的问题，解决了，可这段代码，调用达不到我的目地，不知是怎么回事？
unit funVolume;interfaceuses MMSystem, Dialogs;Type TDeviceName = (Master, Microphone, WaveOut, Synth);function GetVolume(DN:TDeviceName) : Word ;
procedure SetVolume(DN:TDeviceName; Value:Word);
function GetVolumeMute(DN:TDeviceName) : Boolean;
procedure SetVolumeMute(DN:TDeviceName; Value:Boolean);implementation//获取音量
function GetVolume(DN:TDeviceName) : Word;
var
hMix: HMIXER;
mxlc: MIXERLINECONTROLS;
mxcd: TMIXERCONTROLDETAILS;
vol: TMIXERCONTROLDETAILS_UNSIGNED;
mxc: MIXERCONTROL;
mxl: TMixerLine;
intRet: Integer;
nMixerDevs: Integer;
begin
// Check if Mixer is available
nMixerDevs := mixerGetNumDevs();
if (nMixerDevs < 1) then
begin
   Exit;
end;// open the mixer
intRet := mixerOpen(@hMix, 0, 0, 0, 0);
if intRet = MMSYSERR_NOERROR then
begin
   case DN of
     Master : mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_DST_SPEAKERS;
     Microphone :
             mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE;
     WaveOut : mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT;
     Synth : mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_SRC_SYNTHESIZER;
   end;
   mxl.cbStruct := SizeOf(mxl);   // get line info
   intRet := mixerGetLineInfo(hMix, @mxl, MIXER_GETLINEINFOF_COMPONENTTYPE);   if intRet = MMSYSERR_NOERROR then
   begin
     FillChar(mxlc, SizeOf(mxlc),0);
     mxlc.cbStruct := SizeOf(mxlc);
     mxlc.dwLineID := mxl.dwLineID;
     mxlc.dwControlType := MIXERCONTROL_CONTROLTYPE_VOLUME;
     mxlc.cControls := 1;
     mxlc.cbmxctrl := SizeOf(mxc);     mxlc.pamxctrl := @mxc;
     intRet := mixerGetLineControls(hMix, @mxlc, MIXER_GETLINECONTROLSF_ONEBYTYPE);     if intRet = MMSYSERR_NOERROR then
     begin
       FillChar(mxcd, SizeOf(mxcd),0);
       mxcd.dwControlID := mxc.dwControlID;
       mxcd.cbStruct := SizeOf(mxcd);
       mxcd.cMultipleItems := 0;
       mxcd.cbDetails := SizeOf(Vol);
       mxcd.paDetails := @vol;
       mxcd.cChannels := 1;       intRet := mixerGetControlDetails(hMix, @mxcd,MIXER_SETCONTROLDETAILSF_VALUE);       Result := vol.dwValue ;       if intRet <> MMSYSERR_NOERROR then
         ShowMessage('GetControlDetails Error');
     end
     else
       ShowMessage('GetLineInfo Error');
   end;
   intRet := mixerClose(hMix);
end;
end;//设置音量
procedure setVolume(DN:TDeviceName; Value : Word);
var
hMix: HMIXER;
mxlc: MIXERLINECONTROLS;
mxcd: TMIXERCONTROLDETAILS;
vol: TMIXERCONTROLDETAILS_UNSIGNED;
mxc: MIXERCONTROL;
mxl: TMixerLine;
intRet: Integer;
nMixerDevs: Integer;
begin
// Check if Mixer is available
nMixerDevs := mixerGetNumDevs();
if (nMixerDevs < 1) then
begin
   Exit;
end;// open the mixer
intRet := mixerOpen(@hMix, 0, 0, 0, 0);
if intRet = MMSYSERR_NOERROR then
begin
   case DN of
     Master : mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_DST_SPEAKERS;
     Microphone :
             mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE;
     WaveOut : mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT;
     Synth : mxl.dwComponentType := MIXERLINE_COMPONENTTYPE_SRC_SYNTHESIZER;
   end;
   mxl.cbStruct := SizeOf(mxl);   // get line info
   intRet := mixerGetLineInfo(hMix, @mxl, MIXER_GETLINEINFOF_COMPONENTTYPE);   if intRet = MMSYSERR_NOERROR then
   begin
     FillChar(mxlc, SizeOf(mxlc),0);
     mxlc.cbStruct := SizeOf(mxlc);
     mxlc.dwLineID := mxl.dwLineID;
     mxlc.dwControlType := MIXERCONTROL_CONTROLTYPE_VOLUME;
     mxlc.cControls := 1;
     mxlc.cbmxctrl := SizeOf(mxc);     mxlc.pamxctrl := @mxc;
     intRet := mixerGetLineControls(hMix, @mxlc, MIXER_GETLINECONTROLSF_ONEBYTYPE);     if intRet = MMSYSERR_NOERROR then
     begin
       FillChar(mxcd, SizeOf(mxcd),0);
       mxcd.dwControlID := mxc.dwControlID;
       mxcd.cbStruct := SizeOf(mxcd);
       mxcd.cMultipleItems := 0;
       mxcd.cbDetails := SizeOf(Vol);
       mxcd.paDetails := @vol;
       mxcd.cChannels := 1;       vol.dwValue := Value;       intRet := mixerSetControlDetails(hMix, @mxcd,MIXER_SETCONTROLDETAILSF_VALUE);       if intRet <> MMSYSERR_NOERROR then
         ShowMessage('SetControlDetails Error');
     end
     else
       ShowMessage('GetLineInfo Error');
   end;
   intRet := mixerClose(hMix);
end;
end;我的调用代码
if p^.vkCode = 120 then y:=1;
        begin
         Vol := GetVolume(Master);
          setVolume(Master,15530);
          end;
我想达到每按下ｆ9键，就能增加15530的音量，可第一次似乎增加了，第二次按就没有反映了？
不知道是代码的问题，还是我调用的问题？

调试易

如何按下键盘任意键后执行一个操作？

解决方案 »