Mega Code Archive
Hook the keyboard
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Title: Hook the keyboard
This example shows, how the string (Edit1.Text) is broken into symbols. And two messages WM_KEYDOWN and WM_KEYUP are created for each symbol. These messages are brought in the list of the messages. After that, you should create a hook, which processes the messages of this types.
...
type
TMessageList = class(TList);
var
Form1: TForm1;
MessageList: TMessageList = nil;
MessageBuffer: TEventMsg;
HookHandle: hHook = 0;
MessageCount: Word = 0;
Go: Boolean = False;
implementation
{$R *.DFM}
procedure Stop;
begin
if Go then UnHookWindowsHookEx(HookHandle);
MessageList.Free;
Go:=False;
end;
function FBack(Code: Integer; wParam, lParam: LongInt): LongInt; stdcall;
begin
case Code of
HC_SKIP:
begin
Inc(MessageCount);
if MessageCount>=MessageList.Count then Stop
else MessageBuffer:=TEventMsg(MessageList.Items[MessageCount]^);
Result:=0;
end;
HC_GETNEXT:
begin
PEventMsg(lParam)^:=MessageBuffer;
Result:=0;
end
else
Result:=CallNextHookEx(HookHandle, Code, wParam, lParam);
end;
end;
procedure SetHook;
begin
MessageBuffer:=TEventMsg(MessageList.Items[0]^);
MessageCount:=0;
HookHandle:=SetWindowsHookEx(WH_JOURNALPLAYBACK, FBack, hInstance, 0);
Go:=True;
end;
procedure MakeMessage(Key: byte; Mes: Cardinal);
var
MyEvent: PEventMsg;
begin
New(MyEvent);
with MyEvent^ do
begin
message:=Mes;
ParamL:=Key;
ParamH:=MapVirtualKey(Key, 0);
Time:=GetTickCount;
hWnd:=Form1.Handle;
end;
MessageList.Add(MyEvent);
end;
procedure Imitation(KeyCode: Word);
begin
MakeMessage(Lo(KeyCode), WM_KEYDOWN);
MakeMessage(Lo(KeyCode), WM_KEYUP);
end;
procedure SetMessages(S: string);
var
i: Integer;
KeyCode: Word;
begin
i:=1;
repeat
KeyCode:=vkKeyScan(S[i]);
Imitation(KeyCode); // simulate key presses
Inc(i);
until i>Length(S);
end;
function SendStr(S: string): Integer;
begin
try
MessageList:=TMessageList.Create;
SetMessages(S); // set messages
SetHook; // set hook
except
end;
Result:=0;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
Edit2.SetFocus;
SendStr(Edit1.Text);
end;
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