Delphi uses keyboard hooks

I read "deep into windows core programming in Delphi" and thought it was okay to write something. At least I learned something.

So I sorted outCode, And add a note to send it.

The first is the DLL used by the most important keyboard HOOK:

 Unit  Unitdll;  Interface  Uses  Windows;  Const Buffer_size = 16 * 1024 ;// Size of the file mapped to the memory  Const Hook_mem_filename = '  Mem_file ' ;// Image File Name  Const Hook_mutex_name = '  Mutex_name  ' ;// Mutex name  Type // Shared structure tshared = Record  Keys:  Array [ 0 .. Buffer_size] Of Char; keycount: integer;  End  ; // Share Structure pointer pshared = ^ Tshared;  VaR  Memfile, hookmutex: thandle; // File handle and mutex handle holdkeyhook: hhook; // Hook variable shared: pshared; // Shared variable  Implementation // Important: keyboard hook callback  Function Keyhookproc (icode: integer; wparam: wparam; lparam: lparam): lresult;  Stdcall ; Export  ;  Const  Keypressmask = $ 80000000  ;  Begin    If Icode < 0   Then  Result: = Callnexthookex (holdkeyhook, icode, wparam, lparam) Else    Begin      If (Lparam And Keypressmask) = 0 ) Then      Begin // Keyboard Message capture shared ^. Keys [Shared ^. keycount]: = Char (wparam And  $ 00FF); Inc (shared ^. keycount ); // Reset if the memory size exceeds the limit  If Shared ^. keycount> = buffer_size- 1  Then  Shared ^. keycount: = 0  ;  End  ; Result: = 0  ;  End  ;  End  ; // Installation hook  Function Enablekeyhook: bool; Export  ; Begin  Shared ^. keycount: = 0  ;  If Holdkeyhook = 0   Then    Begin // Set hook Filter  {  Wh_keyboard: installed with the keyboard hook keyhookproc: Message callback, hinstance: callback function instance thread ID  }  Holdkeyhook: = Setwindowshookex (wh_keyboard, keyhookproc, hinstance, 0 );  End  ; Result: = (Holdkeyhook <> 0  );  End  ;  {  Undo hook Filter Function  }  Function Disablekeyhook: bool; Export  ;  Begin    If Holdkeyhook <> 0  Then    Begin  Unhookwindowshookex (holdkeyhook); holdkeyhook: = 0  ; Shared ^. keycount: = 0  ;  End  ; Result: = (Holdkeyhook = 0  );  End  ; // How many buttons are obtained?  Function Getkeycount: integer; Export  ;  Begin  Result: = Shared ^. keycount;  End  ; // Obtain the I button  Function Getkey (Index: integer): Char; Export  ;  Begin  Result: = Shared ^. Keys [Index]; End  ; // Clear button  Procedure Clearkeystring; Export  ;  Begin  Shared ^. keycount: = 0  ;  End  ; // Export function list  Exports  Enablekeyhook, disablekeyhook, getkeycount, clearkeystring, getkey; Initialization // Create a mutex variable. Only one DLL process can use hookmutex: = Createmutex ( Nil  , True, hook_mutex_name ); // Open the file image memfile: = Openfilemapping (file_map_write, false, hook_mem_filename ); // If this file image does not exist, it is created.  If Memfile = 0   Then  Memfile: = Createfilemapping ($ ffffffff, Nil , Page_readwrite, 0  , Sizeof (tshared), hook_mem_filename ); // File ing memory shared: = Mapviewoffile (memfile, file_map_write, 0 , 0 , 0  ); // Release the mutex variable releasemutex (hookmutex ); // Turn off the mutex handle closehandle (hookmutex );  Finalization // Remove hook Filter  If Holdkeyhook <>0   Then  Disablekeyhook; // Release the ing unmapviewoffile (shared ); // Disable the image file closehandle (memfile );  End .

After reading this, you can directly write a client to call it.

 

 Unit  Unit2;  Interface  Uses  Windows, messages, sysutils, classes, graphics, controls, forms, dialogs, stdctrls, extctrls;  Type Tform1 = Class  (Tform) memo1: tmemo; bsethook: tbutton; bcancelhook: tbutton; breadkeys: tbutton; bclearkeys: tbutton; panel2: tpanel;  Procedure  Bsethookclick (Sender: tobject );  Procedure  Bcancelhookclick (Sender: tobject );  Procedure  Breadkeysclick (Sender: tobject );  Procedure  Bclearkeysclick (Sender: tobject );  End ;  VaR  Form1: tform1;  Implementation  {  $ R *. DFM  }  Function Enablekeyhook: bool; External   '  Keyhook. dll  '  ;  Function Disablekeyhook: bool; External   ' Keyhook. dll  '  ;  Function Getkeycount: integer; External   '  Keyhook. dll  '  ;  Function Getkey (idx: integer): Char; External   '  Keyhook. dll  '  ;  Procedure Clearkeystring; External   '  Keyhook. dll  '  ;  Procedure  Tform1.bsethookclick (Sender: tobject );  Begin  Enablekeyhook; bsethook. Enabled: = False; bcancelhook. Enabled: = True; breadkeys. Enabled: = True; bclearkeys. Enabled: = True; panel2.caption: ='  The keyboard Hook has been set.  '  ;  End  ;  Procedure  Tform1.bcancelhookclick (Sender: tobject );  Begin  Disablekeyhook; bsethook. Enabled: = True; bcancelhook. Enabled: = False; breadkeys. Enabled: = False; bclearkeys. Enabled: = False; panel2.caption: = '  Keyboard hook not set  '  ;  End  ;  Procedure  Tform1.breadkeysclick (Sender: tobject );  VaR  I: integer;  Begin  Memo1.lines. Clear;  {  Show the hit key history in memo1  }    For I: =0   To Getkeycount- 1   Do  Memo1.text: = Memo1.text + Getkey (I );  End  ;  Procedure  Tform1.bclearkeysclick (Sender: tobject );  Begin  Memo1.clear; clearkeystring;  End  ;  End .