Mouse working only in your application (Views: 28)
Problem/Question/Abstract: I suppose that to somebody it will be he useful this trick. Have I outlined it to me as a simple exercise of those that you tell yourself to yourself ' that would happen if? '. It is that the mouse only works in your application. Neither in the Windows desktop, neither in the window's taskbar, neither in any other place that in your form... Of course, care with him... if you are happened to print something and the driver of your printer it jumps you with the typical message ' papaer empty' you won't be able to close the dialogue that it appears... in short, better you prove it and you see if it is good you for something: Answer: function CallBackDelHook(Code: Integer; wParam: WPARAM; lParam: LPARAM ): LRESULT; stdcall; var DatosMouse: PMouseHookStruct; Intentos: integer; {Esta es la funcion CallBack a la cual llamará el hook.} {This is the CallBack function called by he Hook} begin {Si hay un nuevo evento de raton...} {if there is a new mouse event...} if code = HC_ACTION then begin {Miramos si existe el fichero} {if the mapfile exists} FicheroM := OpenFileMapping(FILE_MAP_READ, False, 'ElReceptor'); {Si no existe, no enviamos nada a la aplicacion receptora} {If dont, send nothing to receiver application} if FicheroM <> 0 then begin Compartido := MapViewOfFile(FicheroM, FILE_MAP_READ, 0, 0, 0); {Apuntamos hacia los datos del evento del raton} DatosMouse := Pointer(lparam); UnmapViewOfFile(Compartido); CloseHandle(FicheroM); end; end; {Llamamos al siguiente hook de la cadena} {call to next hook of the chain} if Compartido^ <> DatosMouse^.hwnd then Result := 1 else Result := CallNextHookEx(HookDeMouse, Code, wParam, lParam); end; and the relevant part is this: if Compartido^ <> DatosMouse^.hwnd then Result := 1 else Result := CallNextHookEx(HookDeMouse, Code, wParam, lParam); that is to say, if the recipient of the message that has captured the hook is our application, we call to the following mouse hook that has installed in the chain, if it is not this way, because we give the message like treaty, miscarrying this way his processed later for the application that is... Well, like in any hook at system level, we will build ourselves first a DLL that is where anger the procedure CallBack of the hook, and then an example application that will communicate somehow with the DLL. Therefore: Hook's DLL library HookMouse; {Demo de Hook de Ratón a nivel de sistema, Radikal.} uses Windows, Messages; type PCompartido = ^THandle; var HookDeMouse: HHook; FicheroM: THandle; Compartido: PCompartido; function CallBackDelHook(Code: Integer; wParam: WPARAM; lParam: LPARAM ): LRESULT; stdcall; var DatosMouse: PMouseHookStruct; Intentos: integer; {Esta es la funcion CallBack a la cual llamará el hook.} {This is the CallBack function called by he Hook} begin {Si hay un nuevo evento de raton...} {if there is a new mouse event...} if code = HC_ACTION then begin {Miramos si existe el fichero} {if the mapfile exists} FicheroM := OpenFileMapping(FILE_MAP_READ, False, 'ElReceptor'); {Si no existe, no enviamos nada a la aplicacion receptora} {If dont, send nothing to receiver application} if FicheroM <> 0 then begin Compartido := MapViewOfFile(FicheroM, FILE_MAP_READ, 0, 0, 0); {Apuntamos hacia los datos del evento del raton} DatosMouse := Pointer(lparam); UnmapViewOfFile(Compartido); CloseHandle(FicheroM); end; end; {Llamamos al siguiente hook de la cadena} {call to next hook of the chain} if Compartido^ <> DatosMouse^.hwnd then Result := 1 else Result := CallNextHookEx(HookDeMouse, Code, wParam, lParam); end; procedure HookOn; stdcall; {Procedure que instala el hook} {procedure for install the hook} begin HookDeMouse := SetWindowsHookEx(WH_MOUSE, @CallBackDelHook, HInstance, 0); end; // stops this type of watch procedure HookOff; stdcall; begin {procedure para desinstalar el hook} {procedure to uninstall the hook} UnhookWindowsHookEx(HookDeMouse); end; exports {Exportamos las procedures...} {Export the procedures} HookOn, HookOff; begin end. Demo application In a clean form, put this code in its unit: unit Unit1; interface uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls; const NombreDLL = 'HookMouse.dll'; type PCompartido = ^THandle; THookMouse = procedure; stdcall; type TForm1 = class(TForm) procedure FormCreate(Sender: TObject); procedure FormDestroy(Sender: TObject); private { Private declarations } FicheroM: THandle; Compartido: PCompartido; HandleDLL: THandle; HookOn, HookOff: THookMouse; public { Public declarations } end; var Form1: TForm1; implementation {$R *.DFM} procedure TForm1.FormCreate(Sender: TObject); begin HandleDLL := LoadLibrary(PChar(ExtractFilePath(Application.Exename) + NombreDLL)); if HandleDLL = 0 then raise Exception.Create('No se pudo cargar la DLL'); @HookOn := GetProcAddress(HandleDLL, 'HookOn'); @HookOff := GetProcAddress(HandleDLL, 'HookOff'); if not assigned(HookOn) or not assigned(HookOff) then raise Exception.Create('No se encontraron las funciones en la DLL' + #13 + 'Cannot find the required DLL functions'); {Creamos el fichero de memoria} FicheroM := CreateFileMapping($FFFFFFFF, nil, PAGE_READWRITE, 0, SizeOf(THandle), 'ElReceptor'); {Si no se creó el fichero, error} if FicheroM = 0 then raise Exception.Create('Error al crear el fichero' + '/Error while create file'); {Direccionamos nuestra estructura al fichero de memoria} Compartido := MapViewOfFile(FicheroM, FILE_MAP_WRITE, 0, 0, 0); {Escribimos datos en el fichero de memoria} Compartido^ := Handle; HookOn; end; procedure TForm1.FormDestroy(Sender: TObject); begin {Desactivamos el Hook} {Uninstall the Hook} if Assigned(HookOff) then HookOff; {Liberamos la DLL} {Free the DLL} if HandleDLL <> 0 then FreeLibrary(HandleDLL); {Cerramos la vista del fichero y el fichero} {Close the memfile and the View} if FicheroM <> 0 then begin UnmapViewOfFile(Compartido); CloseHandle(FicheroM); end; end; end. Note: If you use this technique in an application with several forms, you will put in ' Compartido' the handle of the form that you will activate, but it won't receive mouse events. For example, you can make it in the event OnShow of the form... |