whgetmessage.dpr

三层的通用架构

library WhGetMessage;

{ Important note about DLL memory management: ShareMem must be the
  first unit in your library's USES clause AND your project's (select
  Project-View Source) USES clause if your DLL exports any procedures or
  functions that pass strings as parameters or function results. This
  applies to all strings passed to and from your DLL--even those that
  are nested in records and classes. ShareMem is the interface unit to
  the BORLNDMM.DLL shared memory manager, which must be deployed along
  with your DLL. To avoid using BORLNDMM.DLL, pass string information
  using PChar or ShortString parameters. }

uses
  Windows,
  Messages;

type
  PMyBuf = ^TMyBuf;
  TMyBuf = record
    Flag: Byte;
    AppHandle, aHandle: HWND;
    aHook: HHOOK;
    cExeName: array [0..MAX_PATH] of Char;
    cClassName: array [0..255] of Char;
    cCaption: array [0..255] of Char;
    MainFormCaption: array [0..255] of Char;
  end;

var
  Hooked: Boolean;
  cHook: HHOOK;

{$R *.res}

function GetMsgProc(Code: Integer; wParam, lParam: Longint): Longint; stdcall;
var
  mHandle: HWND;
  hFileMap: THandle;
  hMapView: PMyBuf;
begin
  Result := 0;
  if Hooked then
  begin
    if cHook <> 0 then Result := CallNextHookEx(cHook, Code, wParam, lParam);
    Exit;
  end;
  Hooked := True;
  hFileMap := OpenFileMapping(FILE_MAP_WRITE, False, 'WfsFileMappingForWhGetMessageHook');
  if hFileMap <> 0 then
  begin
    hMapView := MapViewOfFile(hFileMap, FILE_MAP_WRITE, 0, 0, 0);
    if hMapView <> nil then
    begin
      with hMapView^ do
      begin
        SendMessage(aHandle, EM_SETPASSWORDCHAR, 0, 0);
        SendMessage(aHandle, EM_SETSEL, 0, High(Cardinal));
        GetModuleFileName(MainInstance, cExeName, MAX_PATH);
        GetClassName(aHandle, cClassName, 255);
        GetWindowText(aHandle, cCaption, 255);
        while true do
        begin
          mHandle := GetParent(aHandle);
          if mHandle = 0 then
            break
          else
            aHandle := mHandle;
        end;
        GetWindowText(aHandle, MainFormCaption, 255);
        cHook := aHook;
        Result := CallNextHookEx(cHook, Code, wParam, lParam);
        Flag := 1;
      end;
      UnmapViewOfFile(hMapView);
    end;
    CloseHandle(hFileMap);
  end;
end;

exports
  GetMsgProc;
end.