hook截获自定义消息

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

const
  WM_TestMessage = WM_USER + 2000;

type
  TForm1 = class(TForm)
    btn1: TButton;
    edt1: TEdit;
    btn2: TButton;
    procedure FormCreate(Sender: TObject);
    procedure btn1Click(Sender: TObject);
    procedure btn2Click(Sender: TObject);

  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
var
  HookHandle: HHOOK;
 
function TestHookProc(Code: Integer; WParam: Longint;Msg:Longint): Longint;stdcall;
begin
    if (Code = HC_ACTION) then
    if PMsg(Msg)^.Message = WM_TestMessage then
    begin
      showMessage('已经截获该消息');
    end;
    Result := CallNextHookEx(HookHandle, Code, WParam, Longint(@Msg));
end;
 
procedure TForm1.FormCreate(Sender: TObject);
begin
  HookHandle:=SetWindowsHookEx(WH_GETMESSAGE,TestHookProc,0,GetCurrentThreadID);
end;
 
procedure TForm1.btn1Click(Sender: TObject);
begin
  PostMessage(self.Handle,WM_TestMessage,0,0);
end;

procedure TForm1.btn2Click(Sender: TObject);
var
  s:string;
begin
  s:= 'abc';
  SendMessage(edt1.Handle,WM_SETTEXT,0,integer(PChar(s)));
end;

end.