Delphi中如何模拟键盘按键

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可以用JournalPlayback Windows Hook实现 DDG5第13章有个Demo, 你可以去看看。
SendKey.pas内容如下:
unit SendKey;
interface
uses
SysUtils, Windows, Messages, Classes, KeyDefs;
type
{ Error codes }
TSendKeyError = (sk_None, sk_FailSetHook, sk_InvalidToken,
sk_UnknownError, sk_AlreadyPlaying);
{ first vk code to last vk code }
TvkKeySet = set of vk_LButton..vk_Scroll;
{ exceptions }
ESendKeyError = class(Exception);
ESKSetHookError = class(ESendKeyError);
ESKInvalidToken = class(ESendKeyError);
ESKAlreadyPlaying = class(ESendKeyError);
function SendKeys(S: String): TSendKeyError;
procedure WaitForHook;
procedure StopPlayback;
var
Playing: Boolean;
implementation
uses Forms;
type
{ a TList descendant that know how to dispose of its contents }
TMessageList = class(TList)
public
destructor Destroy; override;
end;
const
{ valid "sys" keys }
vkKeySet: TvkKeySet = [Ord('A')..Ord('Z'), vk_Menu, vk_F1..vk_F12];
 
destructor TMessageList.Destroy;
var
i: longint;
begin
{ deallocate all the message records before discarding the list }
for i := 0 to Count - 1 do
Dispose(PEventMsg(Items));
inherited Destroy;
end;
var
{ variables global to the DLL }
MsgCount: word = 0;
MessageBuffer: TEventMsg;
HookHandle: hHook = 0;
MessageList: TMessageList = Nil;
AltPressed, ControlPressed, ShiftPressed: Boolean;
procedure StopPlayback;
{ Unhook the hook, and clean up }
begin
{ if Hook is currently active, then unplug it }
if Playing then
UnhookWindowsHookEx(HookHandle);
MessageList.Free;
Playing := False;
end;
function Play(Code: integer; wParam, lParam: Longint): Longint; stdcal
l;
{ This is the JournalPlayback callback function. It is called by }
{ Windows when Windows polls for hardware events. The code parameter
}
{ indicates what to do. }
begin
case Code of
HC_SKIP:
{ HC_SKIP means to pull the next message out of our list. If we
}
{ are at the end of the list, it's okay to unhook the }
{ JournalPlayback hook from here. }
begin
{ increment message counter }
inc(MsgCount);
{ check to see if all messages have been played }
if MsgCount >= MessageList.Count then StopPlayback
{ otherwise copy next message from list into buffer }
else MessageBuffer := TEventMsg(MessageList.Items[MsgCount]^);
Result := 0;
end;
HC_GETNEXT:
{ HC_GETNEXT means to fill the wParam and lParam with the proper
}
{ values so that the message can be played back. DO NOT unhook
}
{ hook from within here. Return value indicates how much time }
{ until Windows should playback message. We'll return 0 so that
}
{ it is processed right away. }
begin
{ move message in buffer to message queue }
PEventMsg(lParam)^ := MessageBuffer;
Result := 0 { process immediately }
end
else
{ if Code isn't HC_SKIP or HC_GETNEXT, call next hook in chain }
Result := CallNextHookEx(HookHandle, Code, wParam, lParam);
end;
end;
procedure StartPlayback;
{ Initializes globals and sets the hook }
begin
{ grab first message from list and place in buffer in case we }
{ get a hc_GetNext before and hc_Skip }
MessageBuffer := TEventMsg(MessageList.Items[0]^);
{ initialize message count and play indicator }
MsgCount := 0;
{ initialize Alt, Control, and Shift key flags }
AltPressed := False;
ControlPressed := False;
ShiftPressed := False;
{ set the hook! }
HookHandle := SetWindowsHookEx(wh_JournalPlayback, Play, hInstance,
0);
if HookHandle = 0 then
raise ESKSetHookError.Create('Failed to set hook');
Playing := True;
end;
procedure MakeMessage(vKey: byte; M: Cardinal);
{ procedure builds a TEventMsg record that emulates a keystroke and }
{ adds it to message list }
var
E: PEventMsg;
begin
New(E); // allocate a message record
with E^ do
begin
message := M; // set message field
paramL := vKey; // vk code in ParamL
paramH := MapVirtualKey(vKey, 0); // scan code in ParamH
time := GetTickCount; // set time
hwnd := 0; // ignored
end;
MessageList.Add(E);
end;
procedure KeyDown(vKey: byte);
{ Generates KeyDownMessage }
begin
{ don't generate a "sys" key if the control key is pressed }
{ (This is a Windows quirk) }
if AltPressed and (not ControlPressed) and (vKey in vkKeySet) then
MakeMessage(vKey, wm_SysKeyDown)
else
MakeMessage(vKey, wm_KeyDown);
end;
procedure KeyUp(vKey: byte);
{ Generates KeyUp message }
begin
{ don't generate a "sys" key if the control key is pressed }
{ (This is a Windows quirk) }
if AltPressed and (not ControlPressed) and (vKey in vkKeySet) then
MakeMessage(vKey, wm_SysKeyUp)
else
MakeMessage(vKey, wm_KeyUp);
end;
procedure SimKeyPresses(VKeyCode: Word);
{ This function simulates keypresses for the given key, taking into }
{ account the current state of Alt, Control, and Shift keys }
begin
{ press Alt key if flag has been set }
if AltPressed then
KeyDown(vk_Menu);
{ press Control key if flag has been set }
if ControlPressed then
KeyDown(vk_Control);
{ if shift is pressed, or shifted key and control is not pressed...
}
if (((Hi(VKeyCode) and 1) <> 0) and (not ControlPressed)) or
ShiftPressed then
KeyDown(vk_Shift); { ...press shift }
KeyDown(Lo(VKeyCode)); { press key down }
KeyUp(Lo(VKeyCode)); { release key }
{ if shift is pressed, or shifted key and control is not pressed...
}
if (((Hi(VKeyCode) and 1) <> 0) and (not ControlPressed)) or
ShiftPressed then
KeyUp(vk_Shift); { ...release shift }
{ if shift flag is set, reset flag }
if ShiftPressed then begin
ShiftPressed := False;
end;
{ Release Control key if flag has been set, reset flag }
if ControlPressed then begin
KeyUp(vk_Control);
ControlPressed := False;
end;
{ Release Alt key if flag has been set, reset flag }
if AltPressed then begin
KeyUp(vk_Menu);
AltPressed := False;
end;
end;
procedure ProcessKey(S: String);
{ This function parses each character in the string to create the }
{ message list }
var
KeyCode: word;
Key: byte;
index: integer;
Token: TKeyString;
begin
index := 1;
repeat
case S[index] of
KeyGroupOpen:
{ It's the beginning of a special token! }
begin
Token := '';
inc(index);
while S[index] <> KeyGroupClose do begin
{ add to Token until the end token symbol is encountered }
Token := Token + S[index];
inc(index);
{ check to make sure the token's not too long }
if (Length(Token) = 7) and (S[index] <> KeyGroupClose) the
n
raise ESKInvalidToken.Create('No closing brace');
end;
{ look for token in array, Key parameter will }
{ contain vk code if successful }
if not FindKeyInArray(Token, Key) then
raise ESKInvalidToken.Create('Invalid token');
{ simulate keypress sequence }
SimKeyPresses(MakeWord(Key, 0));
end;
AltKey: AltPressed := True; // set Alt flag
ControlKey: ControlPressed := True; // set Control flag
ShiftKey: ShiftPressed := True; // set Shift flag
else begin
{ A normal character was pressed }
{ convert character into a word where the high byte contains }
{ the shift state and the low byte contains the vk code }
KeyCode := vkKeyScan(S[index]);
{ simulate keypress sequence }
SimKeyPresses(KeyCode);
end;
end;
Inc(index);
until index > Length(S);
end;
procedure WaitForHook;
begin
repeat Application.ProcessMessages until not Playing;
end;
function SendKeys(S: String): TSendKeyError;
{ This is the one entry point. Based on the string passed in the S }
{ parameter, this function creates a list of keyup/keydown messages, }
{ sets a JournalPlayback hook, and replays the keystroke messages. }
begin
Result := sk_None; // assume success
try
if Playing then raise ESKAlreadyPlaying.Create('');
MessageList := TMessageList.Create; // create list of messages
ProcessKey(S); // create messages from strin
g
StartPlayback; // set hook and play back messa
ges
except
{ if an exception occurs, return an error code, and clean up }
on E:ESendKeyError do
begin
MessageList.Free;
if E is ESKSetHookError then
Result := sk_FailSetHook
else if E is ESKInvalidToken then
Result := sk_InvalidToken
else if E is ESKAlreadyPlaying then
Result := sk_AlreadyPlaying;
end
else
Result := sk_UnknownError; // Catch-all exception handler
end;
end;
end.
 

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