unit WHookInt;
interface
uses
Windows, Messages, SysUtils,
msxml, Forms, unit2;
function SetHook(WinHandle: HWND; MsgToSend: Integer): Boolean; stdcall; export;
function FreeHook: Boolean; stdcall; export;
function MsgFilterFunc(Code: Integer; wParam, lParam: Longint): Longint stdcall; export;
implementation
// Memory map file stuff
{
The CreateFileMapping function creates unnamed file-mapping object
for the specified file.
}
function CreateMMF(Name: string; Size: Integer): THandle;
begin
Result := CreateFileMapping($FFFFFFFF, nil, PAGE_READWRITE, 0, Size, PChar(Name));
if Result <> 0 then
begin
if GetLastError = ERROR_ALREADY_EXISTS then
begin
CloseHandle(Result);
Result := 0;
end;
end;
end;
{ The OpenFileMapping function opens a named file-mapping object. }
function OpenMMF(Name: string): THandle;
begin
Result := OpenFileMapping(FILE_MAP_ALL_ACCESS, False, PChar(Name));
// The return value is an open
handle to the specified file-mapping object.
end;
{
The MapViewOfFile function maps a view of a file into
the address space of the calling process.
}
function MapMMF(MMFHandle: THandle): Pointer;
begin
Result := MapViewOfFile(MMFHandle, FILE_MAP_ALL_ACCESS, 0, 0, 0);
end;
{
The UnmapViewOfFile function unmaps a mapped view of a file
from the calling process's address space.
}
function UnMapMMF(P: Pointer): Boolean;
begin
Result := UnmapViewOfFile(P);
end;
function CloseMMF(MMFHandle: THandle): Boolean;
begin
Result := CloseHandle(MMFHandle);
end;
// Actual hook stuff
type
TPMsg = ^TMsg;
const
VK_D = $44;
VK_E = $45;
VK_F = $46;
VK_M = $4D;
VK_R = $52;
MMFName = 'MsgFilterHookDemo';
type
PMMFData = ^TMMFData;
TMMFData = record
NextHook: HHOOK;
WinHandle: HWND;
MsgToSend: Integer;
end;
// global variables, only valid in the process which installs the hook.
var
MMFHandle: THandle;
MMFData: PMMFData;
function UnMapAndCloseMMF: Boolean;
begin
Result := False;
if UnMapMMF(MMFData) then
begin
MMFData := nil;
if CloseMMF(MMFHandle) then
begin
MMFHandle := 0;
Result := True;
end;
end;
end;
{
The SetWindowsHookEx function installs an application-defined
hook procedure into a hook chain.
WH_GETMESSAGE Installs a hook procedure that monitors messages
posted to a message queue.
For more information, see the GetMsgProc hook procedure.
}
function SetHook(WinHandle: HWND; MsgToSend: Integer): Boolean; stdcall;
var
test : boolean;
begin
if (MMFData = nil) and (MMFHandle = 0) then
begin
MMFHandle := CreateMMF(MMFName, SizeOf(TMMFData));
if MMFHandle <> 0 then
begin
MMFData := MapMMF(MMFHandle);
if MMFData <> nil then
begin
MMFData.WinHandle := WinHandle;
MMFData.MsgToSend := MsgToSend;
MMFData.NextHook := SetWindowsHookEx(WH_GETMESSAGE, MsgFilterFunc, HInstance, 0);
if MMFData.NextHook = 0 then
UnMapAndCloseMMF
else
Result := True;
end
else
begin
CloseMMF(MMFHandle);
MMFHandle := 0;
end;
end;
end;
end;
{
The UnhookWindowsHookEx function removes the hook procedure installed
in a hook chain by the SetWindowsHookEx function.
}
function FreeHook: Boolean; stdcall;
begin
Result := False;
if (MMFData <> nil) and (MMFHandle <> 0) then
if UnHookWindowsHookEx(MMFData^.NextHook) then
Result := UnMapAndCloseMMF;
end;
(*
GetMsgProc(
nCode: Integer; {the hook code}
wParam: WPARAM; {message removal flag}
lParam: LPARAM {a pointer to a TMsg structure}
): LRESULT; {this function should always return zero}
{ See help on ==> GetMsgProc}
*)
function MsgFilterFunc(Code: Integer; wParam, lParam: Longint): Longint;
var
MMFHandle: THandle;
MMFData: PMMFData;
Kill: boolean;
F: TForm2;
begin
Result := 0;
MMFHandle := OpenMMF(MMFName);
if MMFHandle <> 0 then
begin
MMFData := MapMMF(MMFHandle);
if MMFData <> nil then
begin
if (Code < 0) or (wParam = PM_NOREMOVE) then
{
The CallNextHookEx function passes the hook information to the
next hook procedure in the current hook chain.
}
Result := CallNextHookEx(MMFData.NextHook, Code, wParam, lParam)
else
begin
Kill := False;
{ Examples }
with TMsg(Pointer(lParam)^) do
begin
// Kill Numbers
if (wParam >= 48) and (wParam <= 57) then Kill := True;
// Kill Tabulator
if (wParam = VK_TAB) then Kill := True;
end;
if TPMsg(lParam)^.wParam = VK_Escape then begin
Kill := True;
end;
//MessageBox(0,TPMsg(lParam)^.message,'testme',mb_Ok);
{ Example to disable all the start-Key combinations }
// F.Label1.Caption := 'Test';//inttostr(2);
//F.Label1.Caption := inttostr(TPMsg(lParam)^.wParam );
case TPMsg(lParam)^.message of
// WM_SYSCOMMAND: // The Win Start Key (or Ctrl+ESC)
// if TPMsg(lParam)^.wParam = SC_TASKLIST then Kill := True;
WM_HOTKEY:
case ((TPMsg(lParam)^.lParam and $00FF0000) shr 16) of
VK_D, // Win+D ==> Desktop
VK_E, // Win+E ==> Explorer
VK_F, // Win+F+(Ctrl) ==> Find:All (and Find: Computer)
VK_M, // Win+M ==> Minimize all
VK_R, // Win+R ==> Run program.
VK_F1, // Win+F1 ==> Windows Help
VK_PAUSE: // Win+Pause ==> Windows system properties
Kill := True;
end;
end;
if Kill then TPMsg(lParam)^.message := WM_NULL;
Result := CallNextHookEx(MMFData.NextHook, Code, wParam, lParam)
end;
UnMapMMF(MMFData);
end;
CloseMMF(MMFHandle);
end;
end;
initialization
begin
MMFHandle := 0;
MMFData := nil;
end;
finalization
FreeHook;
end.